Evaluation of photoperiod and thermosensitive genic male sterile lines for hybrid rice seeds production in Kenya

<p>Photo–thermo-sensitive genic male sterile (P(T)GMS) rice is a new hybrid rice technology that uses prolonged<br>light length and high temperatures to induce sterility. This technology is being introduced in Kenya but such<br>growth conditions are lacking in the tropics. To overcome this, we grew P(T)GMS under greenhouse conditions<br>where day light length was prolonged to 14 hrs using solar illumination and day and night temperatures were<br>maintained above 36Cº and 24ºC respectively. Sterility of P(T)GMS was determined by the level of abortive<br>pollen and seed set rates. Hybrid seeds were produced by crossing three P(T)GMS lines (V1PGM, V2TGM and<br>V3PGM) as female lines with Basmati 370 and Basmati 217 varieties as pollen donors. Under long and normal<br>day lengths and high temperatures, pollen sterility ranged from 99-100% but no seeds were set in PGMS lines.<br>However, TGMS recorded 3% and 2% seed set under similar conditions. Under natural conditions both PGMS<br>and TGMS reverted to fertility. Agronomic evaluation showed outstanding (P<0.01) performance of hybrids over<br>parents in flag leaf length (V2370; 35.8 cm), panicle exsertion (V2217; 8cm) and shorter flowering time (V3217;<br>85 days) under greenhouse conditions while flag leaf width (V1370; 1.48 cm) and tillering (100) performed better<br>under natural conditions. Percentage seed set positively correlated with flag leaf related traits and flowering days<br>but negatively correlated with panicle length, panicle exsertion and tillering. We conclude that the P(T)GMS lines<br>are adaptable for hybrid rice seed production in Kenya but there is need to review the P(T)GMS lines’ background<br>so as to minimize incompatibility in hybrids.