Subscribe Now Subscribe Today
Research Article
 

Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length



A.S. Anter
 
Facebook Twitter Digg Reddit Linkedin StumbleUpon E-mail
ABSTRACT

Background and Objective: Wheat bread is classified as the main food crop in Egypt. However, Egypt is the largest importer of wheat globally. The objectives of this study were to increase genetic variation of bread wheat and to identify among mutant lines those with high-yielding under marginal lands conditions. Materials and Methods: Grains of five bread wheat varieties were irradiation by three doses of gamma rays (100,200 and 300 Gy). Fifteen M0 combination seeds along with the mother varieties arranged in randomize complete blocks design with three replicates at Agricultural Production and Research Station of National Research Centre, Egypt, during four winter seasons (2016-2019). The phenotype selection was applied to the M3 generation based on a longer spike length, as a result, twenty-three mutant lines have been created, which considered as putative mutants. To confirm these mutant lines, five distinct mutant lines out 23 mutant lines were reevaluated based on grains yield components in M4 generation. Results: Analysis of variance showed significant variation (p<0.05) among resource mutant lines for quantitative phenotypic traits in mutated generations. Compared to the mother varieties, five mutant lines presented highly outstanding quantitative phenotypic traits. All characters recorded high heritability accompanied with moderate genetic advance, therefore, the possibility of improving wheat grain yield through phenotypic selection. All characters, except plant height, evidenced to be priority traits in selection for higher grain yield due to their powerful direct association with grain yield. Conclusion: These mutant lines provide exciting new valuable resources to investigate and improvement of complex traits in bread wheat.

Services
Related Articles in ASCI
Similar Articles in this Journal
Search in Google Scholar
View Citation
Report Citation

 
  How to cite this article:

A.S. Anter , 2021. Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length. Asian Journal of Plant Sciences, 20: 313-323.

DOI: 10.3923/ajps.2021.313.323

URL: https://scialert.net/abstract/?doi=ajps.2021.313.323
 
Copyright: © 2021. This is an open access article distributed under the terms of the creative commons attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

INTRODUCTION

Bread wheat (Triticum aestivum L.) is the primary crop in Egypt. The rising Egyptians population have resulted an increasing demand for bread wheat in the following years. Wheat grain is used as food for humans and the straw is used as fodder for animals1. However, Egypt is the largest wheat importer in the world due to the limited amount of cultivated land and there is little use of modern farming technology2. Therefore, increasing local production through improving grain yield per unit area becomes a matter of importance.

Plant breeding techniques, mutagenesis, biotechnology genetic engineering and molecular breeding have played a pivotal role in exploiting available germplasm resources to create variability and develop improved cultivars3. In this regard, mutagenesis shows as an easy and effective mean of inducing genetic variation. Several researchers have used mutation breeding to improve grains yield of bread wheat4-6. The main idea of mutation breeding is to identify individuals with a target mutation, which involves two prime steps: mutant screening and mutant confirmation7. Mutant screening is a selection of individuals from a huge population that meet specific selection criteria, such as height, earliness, shape, weight compared to the their parents. Wheat spike is key components for improving grain yield because it is positively correlated with grain yield components such as grains per spike and weight per spike8,9. Most studies have attributed the increased grain yield is due to in increases in grains per spike10, 1000 grain weight or both11. In addition, the spike, non-foliar organ, can be considered as the photosynthetic organ to grain production12,13. Thus, improving grain yield can be achieved by indirect selection for spike length, it has the number of spikelet’s, the number of fertile spikelets and the grains per spike14.

The expected response to selection for studied traits can be estimated by some parameters like phenotypic (PCV) and genotypic (GCV) coefficient of variability, heritability and genetic advance. The GCV measures extent of genetic variability shown by studied trait but it is not possible to determine quantity of variation that is heritable. Estimation of heritability is basically for selection process as it determines the transmissibility of a studied trait in the next generation but does not give a true picture of the expected gain in the next generation. Heritability and genetic advance are two guidelines for determining the genetic control of studied traits and estimate its expected gain from selection in the next generation15. Correlation coefficients are prerequisites to improve any crop16. Knowledge of the correlation between yield and its components is essential in establishing plant selection guidelines for plant selection15. Therefore, the major focus in this study was on selection for a long spike length, non-foliar organ, because it can be detected easily in the field to supply quantitative character data related to grain yield. The objectives of this study were to increase genetic variation of bread wheat and to identify among mutant lines those with high- yielding under marginal lands conditions.

MATERIALS AND METHODS

Plant material and mutagens: The basic strategy for breeding mutations is based on modifying one or more traits of distinct varieties17. Grains of five bread wheat varieties, Sakha 93 (P1), Sids 13(P2), Giza 168 (P3), Gemmeiza 9 (P4) and Maryout 5 (P5) obtained of Agriculture Research Centre, Ministry of Agriculture and Land Reclamation, Egypt. The characteristic of the mother varieties are shown in Table 1.

They were irradiated by three doses of 100, 200 and 300 Gy of gamma rays (Cobalt-60) at the Egyptian Atomic Energy Authority.

M1, M2, M3 and M4 generations: After the irradiation, the experiment was set up using 15 M0 combination seeds along with the mother varieties (as control) in order to obtain M1 plants. The generations (M1 to M4) was grown at the Agricultural Production and Research Station of National Research Centre, El-Nubaria, Al-Buhayrah Governorate, Egypt. The experiment was carried out in a randomized complete block design with 3 replicates during growth seasons (2016-2019). The sowing was done in November, 2016 by hand at the rate of 350 seeds m2 into the 1.2 m length×0.6 m wide, with 3 rows 0.2 m on row distance (plot size = 2.16 m2). Sprinkler irrigation was applied. Out crossing with other varieties was avoided. Weeds were removed by hand throughout the growing seasons. The standard agricultural practice was applied. The soil characteristics presented in Table 2.

At harvest, spikes from main tillers were taken from survival seeds about ~70% as a subvitals mutation. The seeds obtained from the harvested plants in M1 generation were sown to rise M2 generation in 2017. Seeds collected of each combination were sown to rise M3 generation. In 2018, each combination was grown in three replicate six-row plots, 1.2 m long and 0.60 m wide with 20 cm between rows (plot size = 4.3 m2). At harvest, thirty spikes from each combination were selected based on Spike Length (SL),10 cm <, measured from the base of the rachis to the end of the terminal spikelet, Grains per Spike (GS), Grain Yield per Spike (GYS) and 1000 Grain Weight (TGW).

Table 1:Pedigree and characterizes of mother cultivars
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length

Table 2:Physical and chemical properties of the soil
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length

Table 3:
Determination of mother varieties and doses used to generate mutant lines
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length

Selection was delayed to M3 generation due to studied traits produced a huge phenotypic effect that is recognizable on individual plant and called a macromutation. It is known that a macromutations are polygenic in nature18. Twenty-three mutant lines (as putative lines) were resulted as follows: lines numbered from 1-5 resulted from the 200-Gy radiation dose, lines numbered from 6-10 resulted from the 300-Gy radiation dose and lines numbered from 11-23 resulted from the 100-Gy radiation dose. Line number, mother varieties and doses are presented in Table 3.

In M4 generation, five out of 23 mutant lines were sown as previous generations and reevaluated based on previous traits plus to Plant Height (PH), number of spikes/m2 (NH) and Grains Yield ha1 (GYH).

Statistical analysis of quantitative traits: Data of each trait were subjected to a regular analysis of variance of RCBD according to John19. The p-value<0.05 was considered statistically significant. ±: Standard deviations. Phenotypic (PCV) and genotypic (GCV) coefficients of variation for lines were calculated according to method of Singh and Choudhary20 as follows:

Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length

where, Vp, Vg and X are the phenotypic variance, genotypic variance and grand mean of lines, respectively for studied characters. Broad sense heritability (hb2%) estimated as the ratio of the genotypic variance (vg) to the phenotypic variance (Vp) as described by Allard21. According to Johnson and Wichern22, the heritability value of a trait when reaches 80% considered as high, moderate when it ranged from 40-80% and low when it less 40%. The expected genetic advance under selection (GA) as well as GA as percentage of the genotype mean assuming selection of the superior 5% of the genotypes were estimated in accordance with the formula illustrated by Allard 21 as follows:

Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length

where, k is the selection differential at 5% intensity = 2.06, σ2ph: Phenotypic standard deviation, hb2%: Broad sense heritability.

Deshmukh et al.23 categorized genetic advance from selection as percent of mean as low (<10%), moderate (10-20%) and high (>20%). Correlation coefficients were calculated between all the studied traits according to Kashiani and Saleh24.

RESULTS

Genetic variation among mutant lines: Twenty-three mutant lines have resulted from treatment of five wheat varieties seeds by doses of gamma rays (100,200 and 300 Gy). Analysis of variance showed a very highly significant difference (p< 0.05) among the mutant lines for all the studied traits in M3 and M4 generations (Table 4).

The mean square for mutant lines vs. their mother varieties was significant (p<0.05) for all studied traits. Spike length was recorded the maximum coefficient of variation (8.3%), while 1000 grain weight recorded the least coefficient of variation (3.7%) in M3 generation. In M4 generation, grains yield per spike showed the highest value of CV% (11.2), while grains yield ha1 scored the lowest value (5.5%).

Quantitative traits in M3 generation: The mean performance, grand mean and range of genotypes for the studied traits were showed in Table 5 to illustrate the differences between lines and their parents. Five mutant lines (1, 2, 3, 12 and 14) exhibited the higher mean performance for spike length (18 cm <) compared to the mother varieties. Mean performance of mutant lines for spike length ranged from 11.6 cm for line-7 to 18.5 cm for line-14 followed by line-1 (18.2 cm) while mother varieties ranged from 13.2 cm for P3 to 17.6 cm for P5. Grand mean of mutant lines for spike length was 15.9 cm while grand mean of mother varieties was 15.3 cm. In support of these results, Fig. 1 clearly showed that three mutant lines numbered 1 to 3 were longer spike length compare to mother varieties as shown in Fig. 2. Also, Fig. 3 showed that line -14 excelled in spike length compared to its parent and this was evidenced in Fig. 4.

Concerning with grains per spike, five mutant lines (1, 3,4,12 and 17) showed higher grains per spike (75<) compared to their parents (70.2>). Mean performance of mutant lines for grains per spike ranged from 30.0 for line-23 to 87.0 for line-12 followed by line-4 (82.0) while mother varieties ranged from 55.2 for P1 to 70.2 for P4. But, parents achieved the higher grand mean (66.4) compared to grand mean of mutant lines (55.3). In this study, mean performance and grand mean of parents for grains yield per spike was higher than mutant lines. But, mutant lines recorded wide range for this trait ranged from 1.2 g for line -23 to 3.6 g for line -12. Five out of twenty-three mutant lines (6,15,20,21 and 23 ) recorded higher mean performance for 1000 grain weight (45 g <) compared to their parents (44.1g>).

Table 4:Mean squares of ANOVA for the studied traits of M3 and M4 generations
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
S.V.: Source of variation, SL: Spike length, GS: Grains per spike, GYS: Grains yield per spike, TGW:1000 grain weight, PH: Plant height, NH: Number of spikes/m2, SYH: grains yield ha1,**p<0.05, CV: Coefficient of variation, L: Lines, P: Mother varieties. Note that degrees of freedom in M3 generation equal to 22, 44 and 1 for lines, error and lines vs. parents and in M4 generation equal to 4, 16 and 1, respectively

Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
Fig. 1(a-c):
Spike length of mutant lines (1.2 and 3) stated from left side in the M3 generation

Table 5:
Mean performance, grand mean and range of mutant lines for studied traits in M3 generation
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
SL: Spike length (cm), GS: Grains per spike, GYS: Grains yield per spike, TGW: 1000 grain weight, Grand mean, R: Range, L: Lines, P: Mother varieties,± standard error, **p<0.05

Two lines, 20 and 23, recorded the highest 1000 grains weight (46 g) while P4, the highest parent, recorded 44.1 g. Mutant lines showed wide range for 1000 grain weight ranged from 25.0 g for line-16 to 46.0 g for line-20 with grand mean 38.3 while mother varieties ranged from 41.1 g for P2 to 44.1 g for P4 with grand mean 41.7 g. From of M3 generation, five mutant lines (1, 2, 3, 12 and 14) identified based studied traits and consider as putative mutants. To confirm that these mutant lines are true, they reevaluated in M4 generation plus to plant height, number of spikes m2 and grains yield ha1 (Table 5).

Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
Fig. 2:
Spike length of mother variety for mutant lines 1.2 and 3 in M3 generation

Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
Fig. 3:Spike length of mutant line-14 in the M3 generation

With regard to plant height, mean performance of mutant lines for plant height ranged from 80.1 cm for line-14 to 103.2 cm for line-3 with grand mean 88.6 cm (Table 6). While mother varieties ranged from 77.4 cm for P4 to 105.5 cm for P3 with grand mean 89.3 cm. The grand mean of mother varieties and mutant lines are equal. Regarding spike length, mean performance of mutant lines ranged from 15.7 cm for line-14 to 18.4 cm for line-2 with grand mean 17.0 cm. In contrast, mother varieties ranged from 12.2 cm for P3 to 18.3 cm for P2 with grand mean 15.5 cm. The difference between the line-2 and its parent for the spike length was evidenced in the Fig. 5.

For grains per spike, the line 2 had the highest mean performance (90.4) compared to P4, its parent, (80.0) and other parents (85.1>). And grand mean of mutant lines (83.8) was superior to mother varieties (76.7). Regarding grains yield per spike, line 2 showed the highest mean performance (4.8 g) while P4 recorded 3.7 g. Also, grand mean of mutant lines (4.1g) was higher than mother varieties (3.6 g). Furthermore, line 2 was superior in 1000 grain weight (52.0 g) compared to P4 (41.2) and grand mean of mutant lines for 1000 grain weight (45.9 g ) was higher than mother varieties (42.3 g). Mutant lines ranged from 41.2 g for line-14 to 52.0 g for line-2. With respect to number of heads m2 and grains yield ha1, line-2 achieved the highest mean performance (159.3 and 7441.3 kg) compared to P4 (111.2 and 3344.5 kg) and other parents and mutant lines.

Traits selection value: The total variability was expressed in terms of the PCV and GCV. The values of PCV in all the traits were higher than the values on corresponding GCV in M3 and M4 generations (Table 7). In M3 generation, the highest value of GCV (20% <) was recorded for grains per spike (25.9%) followed by grains yield per spike (16.7%). Nevertheless, the smallest GCV was for 1000 grain weight (13.5).

Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
Fig. 4:Spike length of the mother variety for mutant lines-14

Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
Fig. 5:
Spike length of the line-2 on the left side and his parent on the right side in M4 generation

The low differences between values of PCV and GCV values found for studied traits (1.1>). The highest value of heritability found for grains per spike (98.1%). In general, all traits recorded high value of heritability (80.0% <). In the same direction, all traits which recorded a high value of heritability (80%<) were associated with high genetic advance (48.2%>) as % of lines mean, except for spike length was moderate (14.7%).

In M4 generation, the highest value of GCV was recorded for grain yield ha1 (26.3%) followed by 1000 grain weight (11.2%) while grains per spike recorded the smallest value (10.1%). Phenotypic (PCV) and genotypic (GCV) coefficients of variability were low for all studied traits expect grain yield ha1 compared to M3 generation. However, the differences between the two parameters were less (1.1>). High estimate of heritability (99.0%) accompanied with high genetic advance (53.0 %) as % of lines mean was recorded for grain yield ha1. The rest of traits recorded a high value of heritability (81.8% <) accompanied with moderate genetic advance (20.0% >) as % of lines mean. From these results, the genetic variability was presented for studied traits which provide ample opportunity for further selection.

Relationship among studied traits: In this study, data in Table 8 showed correlation coefficients among studied traits illustrated that grain yield ha1 recorded a positive significant correlation with spike length (0.901) grains per spike (0.875), grains yield per spike (0.801 ),1000 grain weight (0.820) and number of spikes/m2 (0.830). Spike length recorded a positive significant correlation with grains per spike (0.840) and 1000 grain weight (0.849).

Table 6:
Mean performance, grand mean and range of mutant lines for studied traits in M4 generation
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
SL: Spike length (cm), GS: Grains per spike, GYS: Grains yield per spike, TGW: 1000 grain weight, PH: Plant height, NH: Number of spikes m2, GYH: Grains yield ha1, Overall mean, R: Range, LSD0.05: Least significant difference

Table 7:Estimates of genetic parameters of studied traits in M3 and M4 generations
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
SL: Spike length, GS: Grains per spike, GYS: Grains yield per spike, TGW: 1000 grain weight, PH: Plant height, NH: Number of spikes m2. GYH: Grain yield ha1, PCV: Phenotypic coefficient of variation, GCV: Genetic coefficient of variation; hb2%: Heritability in broad sense; GA% genetic advance as % of lines mean

Table 8:Correlation coefficients between quantitative traits in M4 generation
Image for - Induced Mutations in Wheat (Triticum aestivum L.) and Improved Grain Yield by Modifying Spike Length
SL: Spike length, GS: Grains per spike, GYS: Grains yield per spike, TGW: 1000 grain weight, PH: Plant height, NH: Number of spikes m2, GYH: Grain yield ha1, **p<0.05

DISCUSSION

In this study, gamma irradiation was used as a strategy for a broad genetic base within bread wheat to improve the efficiency of the breeding programs because the human selection contributed to a long time in the loss of important allelic variance25. Data in the Table 4 showed that presence variation among mutant lines in M3 and M4 generations, indicating that mutant lines did not perform uniformly across different gamma rays. Traits showed that the CV% was less than 20%, indicating that experimental data were not dispersed and traits were not severely affected environment5. Often the mutations are recessive and of low frequency. Thus, the major focus in this study was on phenotypic selection for a long spike length because it can be detected easily in the field to supply quantitative character data related to grain yield. In the M3 generation, some putative mutant lines (1, 2, 3, 12 and 14) were identified by a longer spike length (18 cm <) compared to their parents. To confirm these mutant lines are true, they were screened for the spike length in the M4 generation and found that line 2 recorded the longest spike length (18.4 cm) compared to their parents (18.1 cm)5,6. Wheat spike comprises spikelets, each with several florets. Consequently, an increase in the spike length can be selected concurrently with increased grains per spike26. In this study, plant height trait was estimated in M4 generation which was equal with mother varieties. In the current study, five mutant lines (1,3,4,12 and 17) recorded higher grains per spike (75.0<) compared to their mother varieties (70.2<). Mutant line-12 showed the highest grains per spike (87.0) in M3 generation. While in M4 generation the P5 superior to mutant lines for grains per spike5,26. This finding showed that the increase in the spike length of line 2 had a positive effect on the grain per spike compared to other mutant lines. For grains yield of each spike, mean performance of parents was higher than mutant line in M3 generation, but in M4 generation, the situation changed in desired direction. Because, the mutant line 2 achieved the highest mean performance of grains yield per spike compared to mother varieties and other lines6,8. Regards to 1000 grain weight, six mutant lines (6, 9, 15, 20, 21 and 23) were heavier 1000 grain weight than mother varieties in M3 generation6,8,27. However, these lines had a short spike length (16 cm >) and low grains per spike (45>). In M4 generation, mutant line-2 recorded the highest 1000 grain weight (52.0 g) compared to mother varieties. Grain yield improvement has been significantly connected with increased 1000 grain weight28. In contrast, Xiao et al.29 found that grain yield negatively correlated with1000 grain weight. For both number of spikes m-2 and grain yield ha1, mean performance of mutant lines and mother varieties are equal for number of spikes m-2 in M4 generation. Mean performance of mutant line 2 for grains yield ha1 was higher than mother varieties and other mutant lines4-6,27. The reason for superior mutant lines vs. mother varieties for spike length, grains per spike, grains yield per spike,1000 grain weight and grain yield ha1 may be due to generate of new mutated alleles responsible for increasing these traits. Hence, specific merit of mutation induction is the possibility of winning unselected genetic variation, improvement of one or a few characters of an excellent cultivar is to be modified30. Therefore, the maximize grain yield in bread wheat obtained by manipulating and predicting spike morphology traits such as spike length, grains per spike, grain yield per spike and 1000 grain weight. It noted that grand mean of mutant lines for grains per spike, grains yield per spike and 1000 grain weight in M3 generation were lower than M4 generation. The ranges gained in the M3 generation were higher than M4 generation for studied traits (Table 5 and 6). Due to the variability dive gradually from M2 to M4 generations17.This study identified line 2 as a promising line. Because, it achieved the highest level of performance for studied traits. It was cleared that the use of the spike length character had a positive effect for identifying the distinct mutant among a large number of plants, especially in early generations. The sum variability was showed in terms of the PCV and GCV. In this context, the values of PCV were higher than their corresponding GCV for all studied traits in two mutated generations, which environmental impact was comparatively low on the expression of studied traits. In this study, a narrow gap was found between the PCV and GCV values of studied traits in two mutated generations, indicating that the environmental factors had lower influence on the expression of these characters than the genetic factors. Grains yield ha1 recorded a high value of PCV and GCV, suggesting that this trait is under the influence of genetic control. This indicated that this trait could be improved through hybridization and selection for better yield performance. Heritability and genetic advance give generic behavior of traits which increases the efficiency of selection. High heritability (80% <) was coupled with high genetic (20% <) advance as percent of mean lines observed for studied traits except for spike length was moderate (14.7%) in M3 generation. In M4 generation, grains yield ha1 recorded high heritability coupled with high genetic advance. This indicated that mutation take place in more than one locus17. This indicated that the additive gene action controlled in grains yield ha1 and can easily be selected through phenotypic selection5. All traits, except plant height, recorded a positive and significant correlation with grain yield ha1 indicates that the important role of these traits in determining grain yield, consequently, these traits have priority in selection for higher grain yield. Spike length was positively correlated with grains per spike and grains weight14,31. This indicated that spike length has a great role in improving grain yield ha1 of bread wheat in sandy soil. This finding suggests that crossing between proper mutant lines possessing longer spike length (18 cm<), higher grains per spike (80<) and heavier 1000 grain weight (46 g <) and crossing with commercial cultivars would be given positive results. Another use of these lines is further evaluation under biotic and abiotic stresses with evaluation in many locations for many years. Consequently, broaden genetic variation of bread wheat in Egypt by add a novel genes and give a chance for grain yield improvement. The introduction of a new adaptive allele in the diverse genetic backgrounds may assist to promote grain yield of old or newly developed varieties of bread wheat to balance supply and demand in Egypt.

CONCLUSION

Five varieties of bread wheat were irradiated by three doses of gamma rays to increase genetic variability and to improve grain yield. Twenty -three mutant lines were generated based on spike length in M3 generation. Five out 23 mutant lines were reevaluated based on grain yield components. Mutant lines showed significant variation in the studied traits that were established through phenotypic and genotype coefficients of variation. Several mutant lines were superior to their mother varieties for most studied characters in M3 and M4 generations. High values of heritability associated with moderate genetic gain observed in all studied characters. This indicated these characters were controlled by additive gene effects and selection may be effective for these characters to grain yield improve. All traits, except plant height, recorded a positive and significant correlation with grain yield ha1 indicates that the important role of these traits in determining grain yield. These mutant lines provide exciting new valuable resources to investigate and improvement of complex traits in bread wheat.

SIGNIFICANCE STATEMENT

This study discovered the direct selection for spike length has a positive effect of grain yield of bread wheat that can be beneficial for wheat breeders. This study will help the wheat breeder to use new valuable resources to investigate and improvement of complex traits to uncover the critical areas of grain yield improvement that many researchers were not able to explore.

REFERENCES
1:  2019. Grains production prospects and long run food security in Egypt. Sustainability, Vol. 11.
CrossRef  |  

2:  Abdelmageed, K., X.H. Chang, D.M. Wang, Y.J. Wang, Y.S. Yang, G.C. Zhao and Z.Q. Tao, 2019. Evolution of varieties and development of production technology in Egypt wheat: A review. J. Integr. Agri., 18: 483-495.
CrossRef  |  Direct Link  |  

3:  Lusser, M., C. Parisi, D. Plan and E. Rodríguez-Cerezo, 2012. Deployment of new biotechnologies in plant breeding. Nat. Biotechnol., 30: 231-239.
CrossRef  |  Direct Link  |  

4:  Al-Naggar, A.M., F. Al-Azab, S.E. Sobieh and M.M. Atta, 2015. Variation induction in wheat via gamma-rays and hybridization and gains from selection in derived heterogeneous populations for drought tolerance. Sci. Agri., 9: 1-15.
CrossRef  |  Direct Link  |  

5:  Balkan, A., 2018. Genetic variability, heritability and genetic advance for yield and quality traits in M2-4 generations of bread wheat (Triticum aestivum L.) genotypes. Turk. J. Field Crops, 23: 173-179.
CrossRef  |  Direct Link  |  

6:  Nazarenko, M., Y. Lykholat, I. Grygoryuk and N. Khromikh, 2018. Optimal doses and concentrations of mutagens for winter wheat breeding purposes. Part I. Grain productivity. J. Cen. Euro. Agric., 19: 194-205.
CrossRef  |  Direct Link  |  

7:  Forster, B.P. and Q.Y. Shu, 2012. Plant Mutagenesis in Crop Improvement: Basic Terms and Applications. In: Plant Mutation Breeding and Biotechnology, Shu, Q.Y., B.P. Forster and H. Nakagawa (Eds.). CABI Publishing, Wallingford, ISBN: 9781780640853, Pages: 612.

8:  Koppolu, R. and T. Schnurbusch 2019. Developmental pathways for shaping spike inflorescence architecture in barley and wheat. J. Integr. Plant Biol., 61: 278-295.
CrossRef  |  Direct Link  |  

9:  2019. TaAPO-A1, an ortholog of rice aberrant panicle organization is associated with total spikelet number per spike in elite European hexaploid winter wheat (Triticum aestivum L.) varieties. Sci. Rep., Vol. 9.
CrossRef  |  

10:  Siddique, K.H.M., E.J.M. Kirby and M.W. Perry, 1989. Ear: Stem ratio in old and modern wheat varieties; relationship with improvement in number of grains per ear and yield. Field Crop Res., 21: 59-78.
CrossRef  |  Direct Link  |  

11:  Zhou, Y., Z.H. He, X.X. Sui, X.C. Xia, X.K. Zhang and G.S. Zhang, 2007. Genetic improvement of grain yield and associated traits in the northern China winter wheat region from 1960 to 2000. Crop Sci., 47: 245-253.
CrossRef  |  Direct Link  |  

12:  Aschan, G. and H. Pfanz, 2003. Non-foliar photosynthesis: A strategy of additional carbon acquisition. Flora-Morphol. Distrib. Funct. Ecol. Plants, 198: 81-97.
CrossRef  |  Direct Link  |  

13:  Maydup, M.L., A.J. Guiamet, C. Granciano, J.R. Lopez and E.A. Tambussi, 2010. The contribution of ear photosynthesis to grain filling in bread wheat (Triticum aestivum L.). Field Crops Res., 119: 48-58.
CrossRef  |  Direct Link  |  

14:  2020. Genotypic and phenotypic correlation and path coefficient analysis for yield and yield-related traits in advanced bread wheat (Triticum aestivum L.) lines. Cogent Food Agric., Vol. 6.
CrossRef  |  

15:  Kozgar, M.I., 2014. Mutation Breeding in Chickpea: Perspectives and Prospects for Food Security De Gruyter Open, Beijing, ISBN: 9788376560700, Pages: 138.

16:  2018. Genetic variability induced by gamma rays and preliminary results of low-cost tilling on M2 generation of chickpea (Cicer arietinum L.). Front. Plant Sci., Vol. 9.
CrossRef  |  

17:  Oladosu, Y., M.Y. Rafii, N. Abdullahm, G. Hussin and A. Ramli et al., 2016. Principle and application of plant mutagenesis in crop improvement: A review. Biotechnol. Biotechnolog. Equip., 30: 1-16.
CrossRef  |  Direct Link  |  

18:  Tah, P.R., 2006. Induced macromutation in mungbean (Vigna radiata (L.) Wilczek). Int. J. Bot., 2: 219-228.
CrossRef  |  Direct Link  |  

19:  John, A.C., 1981. Statistical methods (7th ed.). Technometrics, 23: 312-313.
CrossRef  |  Direct Link  |  

20:  Singh, R.K. and B.D. Choudhary, 1978. Biometrical Methods in Quantitative Genetic Analysis. Kalyani Publishers, New Delhi, Pages: 723.

21:  Allard, W.R., 1999. Principles of Plant Breeding. 2nd Edn., Oxford University Press (OUP) Yugoslavia, Pages: 229.

22:  Johnson, R.A. and D.W. Wichern, 1998. Applied multivariate statistical analysis. 4th Edn., Prentice Hall, New Jersey, ISBN: 9780138341947 Pages: 816.

23:  Deshmukh, S.N., M.S. Basu and P.S. Reddy, 1986. Genetic variability, character association and path coefficients of quantitative traits in Virginia bunch cultivars of groundnut. Indian J. Agric. Sci., 56: 816-821.
Direct Link  |  

24:  Kashiani, P. and G. Saleh, 2010. Estimation of genetic correlations on sweet corn inbred lines using SAS mixed model. Am. J. Agric. Biol. Sci., 5: 309-314.
CrossRef  |  Direct Link  |  

25:  Reif, J.C., P. Zhang, S. Dreisigacker, M.L. Warburton and M. van Ginkel et al., 2005. Wheat genetic diversity trends during domestication and breeding. Theoretical Applied Genet., 110: 859-864.
CrossRef  |  

26:  Würschum, T., W.L. Leiser, S.M. Langer, M.R. Tucker and C.F.H. Longin, 2018. Phenotypic and genetic analysis of spike and kernel characteristics in wheat reveals long-term genetic trends of grain yield components. Theor. Appl. Genet., 131: 2071-2084.
CrossRef  |  Direct Link  |  

27:  Kenzhebayeva, S., G. Doktyrbay, F. Sarsu, N. Omirbekova, A. Abekova and D. Tashenev, 2018. Mutant Resources of Spring Wheat to Improve Grain Quality and Morphology. In: Global Wheat Production, Fahad, S., A. Basir and M. Adnan (Eds.)., InTech, New York, pp: 165-180.

28:  Aisawi, K.A.B., M.P. Reynolds, R.P. Singh and M.J. Foulkes, 2015. The physiological basis of the genetic progress in yield potential of CIMMYT spring wheat cultivars from 1966 to 2009. Crop Sci., 55: 1749-1764.
CrossRef  |  Direct Link  |  

29:  Xiao, Y.G., Z.G. Qian, J.J. Liu, X.C. Xia and W.Q. Ji, 2012. Genetic gains in grain yield and physiological traits of winter wheat in Shandong Province, China, from 1969 to 2006. Crop Sci., 52: 44-56.
CrossRef  |  Direct Link  |  

30:  Roychowdhury, R. and J. Tah, 2013. Mutagenesis—A Potential Approach for Crop Improvement. In: Crop improvement: New approaches and Modern Techniques, Hakeem, K.R., P. Ahmad and M. Ozturk (Eds.)., Springer, New York, pp:149-1871.

31:  Ebrahimnejad, S. and V. Rameeh, 2016. Correlation and factor analysis of grain yield and some important component characters in spring bread wheat genotypes. Res. Agron., 49: 5-15.
CrossRef  |  Direct Link  |  

©  2021 Science Alert. All Rights Reserved