Central Agricultural Research Station, Durgapura (Rajastkan)
Eleven rust resistant wheat varieties, exotic and indigenous, were crossed with a common parent, R.S. 31-1, an improved high yielding but rust susceptible local variety, for studying the hybrid vigour and the combining ability of the rust resistant parents. Observations were recorded for a number of characters like plant height, tillering, leaf length and leaf width, spikelets per ear, ear length, 100 grain weight, 75 per cent, flowering, fodder yield and grain yield.
Heterosis is evident in all the characters except ear length, spikelets per ear and 100 grain weight. It is observed that hybrids gave increases in yield of grain from 4.80 per cent, to as high as 35.27 per cent, and for fodder yield from 3.23 to 35.00 per cent. Highest value for heterosis has been observed in tillering where the hybrid E. 220 X R.S. 31-1 showed an increase of about 56 per cent, over the superior parent.
The variety E.G. 1440 from Egypt has shown the best combining ability with R.S. 31-1 for grain yield whereas a black-rust resistant variety from Kenya, E. 220, has shown the best combining ability in respect of fodder yield. Another variety from Kenya, C. 14112, has shown a depressing effect on all the characters studied and in seven of the characters the decrease over the superior parent is maximum in the cross involving this variety.
