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Das B.,Horticulture and Agro Forestry Research Programme | Jana B.R.,Horticulture and Agro Forestry Research Programme | Dey P.,Horticulture and Agro Forestry Research Programme | Nath V.,Central Horticulture Experimental Station
International Journal of Fruit Science | Year: 2011

Investigations were undertaken to develop a better understanding of assimilate partitioning behavior in litchi, with respect to the role of stored assimilates translocated from other sources in the plant during the fruiting season. The first experiment examined the fruit growth pattern in the litchi 'Shahi'. The second experiment focused on the limitation of assimilate supply to litchi fruits by leaf removal and girdling. The third experiment was aimed at fulfilling the assimilate requirement of growing litchi bunches through current photosynthesis by foliar application of a photosynthesis enhancer (triacontanol). The fruits exhibited a sigmoidal growth pattern with a phase of rapid growth 40 to 60 days after fruit set. Irrespective of method or distance of source limitation, the maximum percent of fruit drop was observed when the source limitation treatments were imposed 30 days after fruit set. Source limitation at all the distances resulted in significant increases in percent of fruit drop over those with no source limitations. With respect to different treatments, all forms of source limitation resulted in significant increase in fruit drop over the control. The results suggest that a contribution of carbohydrate from current photosynthesis for partial fulfillment of total carbon demand of growing fruits is necessary. Only no limitation of current photosynthesis contributed towards 0% loss in fruit weight while a limitation of carbohydrate translocation (girdling) contributed towards an 8.5% loss in fruit weight. However, under the condition of limited carbohydrate translocation, restriction on current photosynthesis caused a 19.1% loss in average fruit weight. Studies on foliar application of photosynthesis enhancers (triacontanol) on fruit drop in litchi under restricted (girdled) and unrestricted translocation of assimilate from other parts of the plant were conducted. These indicated a reduction in the rate of fruit drop with an increase in the concentration of triacontanol in case of unrestricted translocation of assimilate. However, under restricted assimilate translocation, increasing concentrations of triacontanol did not result in reducing the percent of fruit drop. Hence, the study clearly indicated the major role of translocated assimilates from other plant parts in fulfilling the assimilate demand of growing fruits in litchi where current photosynthesis ontributes partially towards assimilate demand. © Taylor & Francis Group, LLC.


Jana B.R.,Horticulture and Agro Forestry Research Programme | Rai M.,Horticulture and Agro Forestry Research Programme | Nath V.,Horticulture and Agro Forestry Research Programme | Das B.,Horticulture and Agro Forestry Research Programme
Acta Horticulturae | Year: 2010

The eastern plateau and hilly agro-climatic zone offers suitable climatic conditions for successful cultivation of papaya. It is being grown in the region since last 30 years particularly under homestead conditions. However, for commercial cultivation of papaya in the region, identification of suitable variety is of prime importance. So far, varietal evaluation in this direction has not been carried out under Jharkhand conditions. Hence, the present investigations were undertaken to identify suitable variety of papaya for commercial cultivation under Jharkhand conditions. Under this, an experiment was conducted during 1998-2000 to evaluate fifteen papaya hybrids/selections for vegetative growth, yield and quality attributes. The cultivars 'Pink Flesh Sweet' and 'Ranchi' had minimum number of internodes to first flower (48.26 and 48.66). Minimum distance (110.01 cm) from base to first fruit harvest was observed in case of the variety 'Pusa Dwarf'. The variety 'Ranchi' recorded maximum individual fruit weight (2.04 kg), yield (34.92 kg/plant) and total sugars. Petiole length was observed to be minimum in the variety 'CO-4' (27.30 cm), the leaf size (length 30.71 cm; breath 29.32 cm) also followed the same pattern. The variety 'CO-3' accounted for the maximum fruit number (51.0) per plant. The maximum pulp thickness was found in 'Singapore' variety while the lowest cavity diameter was found in the variety 'CO-7'. The variety 'Pink Flesh Sweet' had the maximum TSS and total sugars. The preliminary evaluation suggested that the varieties 'Ranchi' and 'CO-3' performed better under Jharkhand conditions. The varieties that could be useful as parents for improvement in future papaya breeding programmes were suggested.

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