Adaptation of recommended rice varieties for unfavorable agro-ecosystems in Ilocos [Philippines]

The evaluation of recommended rice varieties for drought, saline and submerged areas was done in Ilocos Norte and Ilocos Sur from 2010-2012. Treatments were laid out in RCBD with three replications. PSB Rc82 was used as the check variety for drought and saline setups while Raminad, a traditional variety, for the submerged setup. The drought trials were establihsed in Dingras, Ilocos Norte, the saline setups in Pauquin setups in Pasuquin, Ilocos Norte and Ilocos Sur from 2010 to 2012. Treatments were laid out in RCBD wth three replications. PSB Rc82 was used as the check variety for drought and saline setups while Raminad, a traditional variety, for the submerged setup. The drought trials were established in Dingras, Ilocos Norte, the saline setups in Pasuquin, Ilocos Norte and Sta. Catalina, Ilocos Sur, and in Currimao, Ilocos Norte for the submerged trial. Results of the drought trial (2010 and 2011 WS) showed that PSB RC80, NSIC Rc146, Rc158 and Rc192 were comparable to PSB RC82 in terms of grain yield. Yield was significantly higher when wet-direct seeded than when transplanted (3.57 t/ha vs. 3.20 t/ha), with earlier maturity by 10 days. the most preferred varieties were PSB Rc80, Rc82 and NSIC Rc192. The most adaptable saline varieties in Pasuquin (2010 WS and 2011 DS) under slightly saline condition (1 to 8.3 d S/m) were PSB Rc88 and Rc90; NSIC Rc182, Rc184, and Rc190, which were all comparable to PSB Rc82. The most preferred entries were all comparable to PSB Rc82. The most preferred entries were PSB Rc82 and NSIC 190. Higher salinity level (5 to 11.7 dS/m) was observed in Sta. Catalina in 2011 and 2012 WS. The most adaptable varieties were NSIC Rc182, Rc184, Rc196 and Rc190, which showed comparable yield with PSB Rc82. The most preferred varieties were NSIC Rc182 and Rc190. PSB Rc88 and Rc90 showed good performance in Pasuquin, however, in Sta. Catalina, these varieties had low yield. NSIC Rc182, Rc184 and Rc190 showed consistent performance in both sites. For the submergence trial in 2010 and 2011 WS, Los Baños produced the highest yield (2558 kg/ha) in 15-30 DAT flooded condition.