Anther culture response of some rice genotypes with varying amylose content to nitrogen fertilizer

The results indicated that anther culture response is not solely attributed to the genotype (G), nitrogen (N), and season (S), but also to their interaction. Analysis of the data showed that callus induction was significant in the interaction of the three factors (GxNxS) while no such effect was noted on plant regeneration. Green plant regeneration was significantly affected by the interaction of genotype and nitrogen application (GxN). Callus induction of all genotypes was enhanced with increasing level of nitrogen fertilizer until their respective optimum level was reached. Except for IR64 and IR65489H, all genotypes had better callus formation when donor plants were cultivated under optimum nitrogen fertilization, especially during the wet season. Inpite of the high levels of callus formation, plant regeneration was very low suggesting that the two characters are independently inherited. Anther culture efficiency (number of green plants regenerated/total number of anthers plated) was influenced by the quality of the calli formed, which in turn, was affected significantly by the interaction of genotype and nitrogen fertilization (GxN). Embryogenic type of callus exhibited excellent plant regeneration ability while the non-embryogenic type had poor regeneration ability. Four genotypes, IR65, IR65489H, UPL Ri1, and UPL Ri7 had their highest anther culture efficiency when donor plants received 135 kg/ha N. IR64, IR68, and Taipei 309 (control) gave the best results at 90 kg/ha N application. Under their respective optimum nitrogen fertilization, the anther culture efficiency of these genotypes followed a decreasing sequence: Taipei 309IR65489HUPL Ri7IR68IR64IR65UPL Ri1. To find a potential marker in predicting and choosing genotypes responsive to anther culture, amylose content was used as a selection index. The results showed poor association between the amylose content in the grains and anthers. This indicated that amylose content may not be a good correlative character for screening rice genotypes responsive to anther culture