Department of Horticulture, Punjab Agricultural University, Ludhiana 141 004
The experiment was conducted on 9-year-old trees of peach Flordasun and Shan-i-Punjab to investigate the cause(s) of blossom-end. The distribution of N in the upper, middle and lower fruit portions of both the cultivars was studied and compared during the fruit development period. The competition from 1 March 1990 to 10 May 1990 among fruits, leaves and twigs supporting the leaves was also studied during fruit development period in Shan-i-Punjab and Flordasun. The mean N content in the whole fruit of Shan-i-Punjab was higher than the Flordasun fruit. The upper fruit portion of Shan-i-Punjab was signifciantly higher in N content than those of Flordasun. The middle and lower fruit portions of Shan-i-Punjab were also higher in N content than those of Flordasun but difference was not significant. On the other hand, at the time of ripening the concentration of N in middle and lower fruit portions of Flordasun was higher than that of Shan-i-Punjab. This condition appeared to predispose the Flordasun fruit to tip breakdown process by disturbing the N balance with Ca or probably by accelerating the synthesis of cell-well degrading enzymes. The manner of competition for N among different competing units like fruits, leaves and twigs supporting the leaves was variable and stage specific in both the cultivars.
