Cummings Laboratory, Indian Agricultural Research Institute, New Delhi-110012.
*Part of the thesis submitted by the first author for Ph.D. degree of the Indian Agricultural Research Institute, New Delhi.
With a view to study the performance of winter wheats in crosses with spring wheats, eight winter and three spring exotic varieties were crossed with five high yielding Indian spring varieties of different heights. All the 55 F1’s and sixteen parents were studied in rabi 1970–71. Data on grain yield per plant, number of effective tillers per plant, number of grains per ear, weight of grains per ear, 100-grain weight, plant height and number of days to flower, were recorded.
Heterosis as compared to mid parents and better parents was calculated for all the characters. Heterosis to the extent of 193% was observed for grain yield in the winter × spring wheat cross B 5028 A-11-10-2 (V35) × Sharbati Sonora, when compared to the mid parent. The highest positive value was for the cross Benhur (V 11) x Hira. Only few crosses showed significant values of heterosis for number of tillers per plant, number of grains per ear, weight of grains per ear and 100 grain weight. Almost all the hybrids flowered a little late compared to their early parents. In general, the winter varieties B 5028 A-l 1-10-2 (V 35) and Red Coat (V 36) showed good compatibility with all the males involved. The possibility of using the genetic potentialities of the winter wheats in the improvement of spring wheat was discussed.
