Publisher: Bachudo Science Co. Ltd

Screening For Drought Tolerance In Rice (ORYZA SATIVA L.) At Both The Vegetative and Reproductive Stages of Growth

P. I . Okocha
KEYWORDS: Rice breeding lines, drought tolerance, percentage spikelet fertility, drought recovery and rate of leaf senescence.

ABSTRACT:

One hundred advanced rice breeding lines were screened for drought tolerance at both the vegetative and reproductivestages of growth at Umudike (Abia State, Nigeria) and Abakaliki (Ebonyi State, Nigeria) in 2000, while in 2001, 91 and 77 rice breeding lines were screened at Umudike and Abakalili respectively. Drought tolerance at the reproductive stage was measured as percentage spikelet fertility. At the seedling stage, drought tolerance and recovery from drought stress were taken at Abakaliki while at Umudike, drought tolerance and rate of leaf senescence were taken. Rice plants were planted in polythene bags for root length and weight characteristics. Results of the experiments in Umudike show that 32% of the rice lines had resistant/tolerant drought scores while 68% recorded susceptible drought scores, out of which 29% were highly susceptible. At the seedling stage, only 17% were resistant/tolerant while about 83% were susceptible. A Abakaliki, 95% of the rice lines were resistant/tolerant at the reproductive stage while 45% were resistant/tolerant at the. seedling stage. 36% showed signs of recovery from drought stress after water supply was restored. Rate of leaf senescence did not show any clearly defined trend in relation to drought score. In 2001, 72. 7% of the rice lines were resistant/tolerant at reproductive stage while 26.3% of the viable rice lines were resistant/tolerant at the seedling stage. There does not seem to be any relationship between drought score and root length and weight. The most resistant/tolerant rice lines in both locations in the two years were TOX 3445-14-2-3 and SIK 289-54-2-2-2-2-1 with a score of between 1 and 3 at both the vegetative and reproductive stages.   


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