EVALUATION OF WHEAT MUTANT LINES FOR YIELD AND YIELD COMPONENTS UNDER DIFFERENT SOWING DATES

Abstract

The affects of sowing time and heat stresses on yield and yield components
were evaluated in 21 mutant wheat lines under normal and late sowings. Terminal
heat stresses (>30oC) during reproductive phase of the crop from last week of
February to end of March, severely affected the physiological maturity of the crop.
Reductions in various traits were observed, in general, in most of genotypes at late
sowing. Plant height, 1000-grain weight, grain filling period, maturing time and
main spike yield were highly affected under late sowings as compared to other
traits. At normal sowing, 12 mutant lines showed early maturity than local check,
T.J-83, three matured earlier than Kiran-95 and Sarsabz. Seventeen lines took more
time to grain filling period than T.J-83, and 12 mutant lines more time than Sarsabz
and Kiran-95. Fourteen mutant lines had significantly higher 1000-grain weight
(>33g) than T.J-83 and eight had higher weight (>42g) than Sarsabz at normal
sowing, whereas sixteen had more 1000-grain weight (>32.4 g) than T.J-83 and four
than Sarsabz (>38.4g) at late sowing, indicated more tolerance to high temperature
than other genotypes. Mutant lines MASAR99-22, MASAR99-31, MASAR99-37,
MASAR99-03 and MASAR99-14 showed less reduction (2.8 to 8.0%) in 1000-
grain weight under late sowings, and thus showed tolerance to high temperatures
than the other genotypes