Grape fruit (Citrus paradisie Macf) is an important member of citrus family. Out of total citrus area of Pakistan 196.1 thousand hectares, grape fruit is cultivated on an area of 35.3 thousand hectares (Anonymous, 1997). The shape of tree is much beautiful and attractive and can be used in the house lawns during land scaping which can enhance the asthetic value of the lawns. The fruit is much liked by the people for its nutritional values especially its richness in vitamin-C. Grape fruit is a best natural treatment for diabties and doctors usually recommend it for diabetic patients. The fruit contains a large amount of juice and mostly used by the people for its juice contents. Some varieties are more juicy and give higher production than others. Soil and climatic conditions also affect the performance of various cultivars and by changing the location, the performance may also be changed. While studying growth characteristics of grape fruit varieties, it was found that marsh seedless produced more yield than shamber, although, height, spread and total soluble solids of both the cultivars did not vary greatly (Noulmer and Sinthy, 1991). Fruit size and fruit weight of different grape fruit varieties was found variable. The comparison of red maxican and foster grape fruit varieties showed that red maxican produced heavier and bigger fruits, the quality of both the varieties did not show any variation (Baulker and Kornas, 1992). Size of fruit and texture of juice vesicles was found almost equal in shamber and marsh seedless cultivars of grape fruit, but more juice contents and juice percentage was observed in the fruits of march seedless (Elmans and Jokera, 1992).
Keeping in view the above mentioned facts, this project was envisaged to compare four varieties of grape fruit.
Materials and Methods
The research studies were carried out at Horticultural Research Station, Dera Ghazi Khan during 1997-99. Four plants from each of four cultivars of grape fruit viz. Shamber, marsh seedless, foster and red maxican were selected for the experiment. All the plants were uniform in size and of 10-12 years age. They were growing under similar groclimatic conditions. A constant dose of fertilizers and farmyard manure was applied to all the plants on the following rates:
||Farm yard manure
||= 40 kg/plant (during December)
||= 1 kg/plant (half dose before flowering and the 2nd half after fruit setting)
||= 3 kg/plant full dose before flowering along with first dose of urea
||= 1 kg/plant full dose before flowering alongwith first dose of urea
The four varieties of grape fruit were considered as treatments:
Various parameters observed for these varieties were as under:
||Stem girth, height and spread of plant was measured in April
||Yield in the form of number of fruits was calculated on 30th June because fruit stealing was a great limitation to take the yield data afterwards
||Fruit size, weight, TSS, juice contents and juice percentage was observed in the mid of January because after that no fruit was left on the trees
The experiment was laid out according to the randomized complete block design and difference among treatment means was calculated using DMR test (Steel and Torrie, 1980).
Results and Discussion
The results procured on various parameters for both the years are given in Table 1 and 2 and discussed as under.
Stem girth (cm): Table 1 depicts highly significant results for the year 1997-98. T3 produced the maximum stem girth (59.7 cm). This was followed by T2 and T1 and both of them were statistically at par. T4 produced the lowest stem girth. During 1998-99 T1, T2 and T3 behaved similarly with minor differences by producing 52.1, 54.2 and 53.1 cm stem girth, respectively (Table 2). T4 behaved similarly as in the first year and produced lowest stem girth.
|Table 1:|| Comparative studies on the performance of some grape fruit varieties under soil and climatic conditions of Dera Ghazi Khan (1997-98)
||Comparative studies on the performance of some grape fruit varieties under soil and climatic conditions of Dera Ghazi Khan (1998-99)
Number of fruits per plant upto 20th June: During 1997-98 T2 got the highest position by producing 133 fruits. The remaining cultivars appeared in descending order of T3, T4 and T1 by producing 114.4, 78.6 and 63.20 fruits per plant, respectively (Table 1). During second year T4 (120 fruits) got the supreme position (Table 2) followed by T3, T1 and T2 from which 117.2, 107.01 and 78 fruits per plant were counted.
Fruit size (cm2): Maximum sized fruits were obtained from T4 in both the years (Table 1, 2). During first year the maximum fruit size was 221.00 cm2 which was 206.9 cm2 in the following year. The fruit size was found decreasing for T3, T1 and T2 with 189.6, 174.1 and 151 cm2, respectively for the first year. For the next year this sequence was 194, 178.8 and 155.6 cm2 for these treatments.
Average weight of single fruit (gm): Depending on the fruit size, the same trend was observed for weight of fruit (Table 1, 2). Maximum average weight per fruit was observed in T4 in both the years by producing 448.2 and 422.1 gm weight per fruit during first and second year. The remaining treatments were noted in descending order for T3, T1 and T2 with 428.6, 370.8 and 348.4 gm weight per fruit in the first year which were 376.4, 345.4 and 321.6 gm during the following year.
Juice contents (ml): Table 1 and 2 advocates highly significant results. Same pattern was observed for both the years. During 1997-98 maximum juice contents (242.2 ml) were calculated in T2. This was followed by T1, T3 and T4 by producing 205.6, 187.1 and 127.9 ml juice, respectively. In the second year, T2 produced maximum juice contents. Other treatments were found in descending order for T1, T3 and T4 with 223.7, 198.7 and 177.10 ml juice contents respectively.
Juice percentage (%): All these cultivars depicted similar results in both the years. During first year T2 occupied the top position which was statistically similar to T1. Next position was obtained by T3 with 43.7% juice.
The lowest juice percentage was observed in T4. During second year T2 and T1 were found at par statistically by producing 60.05 and 59.40% juice. Then came T3 with 52.29% juice. T4 was observed at the bottom having 45.34% juice in its fruits.
Height and spread of plant and TSS: All the three parameters were found statistically similar for both the years as is evident from Table 1 and 2. Hence no need of discussion of these factors.
Some parameters regarding vegetative or reproductive growth of various cultivars of the grape fruit were found similar while others were observed different. These results reflect the genetic potential of each cultivar, because no treatment was given to any plant except a constant dose of farm yard manure and fertilizer to all the plants. Our results are in accordance with the findings of Baulker and Kornas (1992) and Elmans and Jokera (1992).