The study focused on phenotypic and genetic factors underlying early morning flowering traits in rice in the hope that rice genetic improvement in the warming future will be made possible. Quantitative trait loci (QTL linked to early morning flowering (EMF) traits was analyzed by selective genotyping of phenotypic extremes among 684 BC 1 F 2 lines (derived from the cross PSB Rc82 x WAB56-125) under glasshouse condition was undertaken using single marker analysis (SMA). Four parameters of flower opening time or start time (FOT), peak of flowering (POF), flower mostly closed (FMC), and flower closed (FC) time were recorded. Results of SMA revealed three markers possibly linked to FOT on chromosome 5, 7, and 9, while 6 markers were possibly linked to POF, FMC and FC time on chromosomes 5, 7, 8, 9, and 11. Generally, markers on chromosomes 5, 7 and 9 indicated QTLs controlling EMF during flowering stage in rice. While this needs to be confirmed using a larger population size and other mapping methodology, the results could already be useful for further fine mapping and eventually for marker-assisted selection of heat escape rice cultivars in the future.

In the Philippines, rainfed rice is grown on about 1.3 million hectares or 33% of the total rice area of 4 million hectares. With unpredictable weather, highly variable and heterogenous soils, the evaluation of recommended location specific rainfed rice varieties was done at CSU Piat from 2013WS to 2014WS. Treatments were laid out in RCBD with three replications. Twelve sahod ulan varieties were evaluated for yield, yield components and agronomic traits. PSB Rc14 was used as the check variety for rainfed while PSB Rc82 and NSIC Rc222 as farmers preferred variety in the locality. Across seasons, results showed significant differences in yield which is attributed to varietal and genetic differences of materials tested. NSIC Rc284 obtained the highest mean yield (4.2 ton/ha) with medium maturity of 110.67 days. Second highest yielder were NSIC Rc288 and NSIC Rc276 (3.89 and 3.88 ton/ha) with maturity of 94 and 92 days respectively. These are the top 3 selections specifically adapted at CSU Piat condition. These results/selections provide farmers an option of increasing yield and income using the right rainfed variety even in highly variable rainfed ecosystem.