Fertility restoration and agronomic performance of hybrid rice derived from CMS × NPT under optimum and low nitrogen environments

The use of cytoplasmic male sterility (CMS) is a promising strategy for combining the potential of a new plant type (NPT) rice (Oryza sativa L.) to develop superior hybrids.However, another important aspect to consider is how well the plants can adapt to different environments.The objective of this experiment was to evaluate several CMS × NPT hybrid rice and identify hybrids with high productivity in both optimum and low-N environments.This study was conducted at the IPB University Experimental Station at Babakan, Indonesia, using a randomized complete block design (RCBD) with three replicates in each environment.The genetic material used consisted of several rice hybrids resulting from crosses of four CMS lines with eight NPT lines, as well as six commercial varieties as controls.The result showed that 52.94% of genotypes were partially fertile.Genotype × Environment interactions had a significant effect on most of the observed traits (p < 0.05).Several hybrids showed higher grain yields than some of the control varieties and comparable to others.One genotype had a yield stability index of 0.99, which was higher than that of all control varieties.The PCA analysis showed that PC1 (57.6%) was associated with yield components, while PC2 (42.2%) was associated with tolerance variation.The multi-trait genotype-ideotype distance index (MGIDI) selected five genotypes in an optimal environment.These findings emphasize the importance of NPT as a source of restoration in the development of hybrids that perform optimally with optimum N input and tolerance to low N conditions.