ISOLATION OF PARTHENOCARPIC TROPICAL GYNOECIOUS LINES IN CUCUMBER (CUCUMIS SATIVUS)

Three tropical gynoecious cucumber lines were developed at first time in India at Indian Agricultural Research Institute, New Delhi by More and Seshadri (1988). Further efforts were diverted by the Senior author to develop the parthenocarpic tropical gynoecious cucumber lines with yellow skinned fruits similar to that of cv. Poona Khira primarily grown in Maharashtra state. Thirteen lines (F6) with yellow skinned fruits and six lines which produce green skinned fruits and true breeding for gynoecy were isolated from a complex cross [(Table Green 68 x SC3, F2) x Poona Khira] F3 x [(GY 14 x Table Green 68, F1) x Poona Khira] F3. These 19 lines were further evaluated for skin colour, gynoecy and parthenocarpic nature during Kharif, 1996 and Spring-Summer, 1997. Among the 13 yellow skinned parthenocarpic tropical gynoecious lines four namely, PKG-1-2, PKG- 1-11, PKG-1-12 and PKG-1-15 were found to be 100 per cent parthenocarpic. Similarly among the six green fruit skinned lines three viz., PKG-1-21, PKG-1-23 and PKG-1-24 showed 100 per cent parthenocarpic nature. In the remaining yellow/ green fruit skinned lines the parthenocapy ranged from 82.6 to 96.0 per cent. Thus seven parthenocarpic tropical gynoecious yellow and green skinned fruits which showed 100 per cent parthenocarpy were evaluated for their horticultural characters during Kharif, 1998 in plastic greenhouse. PKG-1-15, PKG-1-12 and PKG-1-24 were found to be promising for earliness while PKG-1-15 and PKG-1-21 exhibited high yield potential compared to the others. Further study is in progress on how this parthenocarpic gene operates in F1 hybrids when the pure parthenocarpic tropical gynoecious line is crossed with monoecious male parent.