Corn improvement for drought resistance
1991
Yodsaporn Chantachum | Charas Kitbamroong | Pichet Grudloyma (Nakhornsawan Field Crops Research Center, Nakhon Sawan (Thailand))
KK-DR Corn population was synthesized in 1982 by mixing equal amount of seed from selected ears (primarily based on synchronization, plant type, standability, size of ears and stay-green under drought stress condition) of 6 different corn varieties. The varieties included Suwan 1 C7, Pakchong 1602, Thai CMR 6, Caripeno C4F2, Texpeno-C17 and Mixed DR. The population was grown in isolation without conscious selection for 2 generations and designated as KK-DR. Three cycles of S1-recurrent selection were used to improve the population for drought resistance. In the first and second cycle of selection, the population was self-pollinated from the selected drought resistant plants. The S1-progenies per se were tested under stress condition by stop irrigation 10 days before pollination. In the third cycle, S1 progenies were made under normal condition and tested under normal and stress condition in dry season 1987. Forty S1-progenies were selected based on drought index and recombined in half-sib recombination block. The KK-DR cycle of selection C1, C2, C3 and a check entry Suwan 1 [SW1(MMS)C2F2] were evaluated for the changes brought about by selection for drought tolerance in the population in 2 years. In 1988, rainy season, the average result covers 5 locations and showed that C1, C2, and C3 yielded 705, 760 and 657 kg/rai respectively compared to 762 kg/rai of Suwan 1. At Nakhon Sawan Field Crops Research Center in 1989 dry season under stress condition, C1, C2, C3 yielded 159, 186 and 208 kg/rai higher than Suwan 1 (122 kg/rai) 30 %, 52 % and 70 % respectively. The population KK-DR(S)C3 seems to be more suitable for planting in drought environment than Suwan 1.
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