Stability and adaptability of promising hybrid rice genotypes in different locations of Bangladesh

Rice has a special significant position as a source of food providing over 75% of Asian’s staple food and more than three billion of world population’s meal which represents 50 to 80% of their daily calorie intake.1,2 This population will increase to over 4.6 billion by 2050.3 which will demand more than 50% of rice needs to be produced what is produced present to cope with the growing population.4,5 Yields of improved inbred rice varieties in favorable conditions have reached to a plateau or even subsequently declined in many countries including Bangladesh. It is recommended that a large number of high yielding rice with high adaption capability to diverse environments is required to accomplish specific socio-economic and agricultural needs. To meet the challenge of producing more rice under those constraints, we need new technologies like hybrid rice because it gives 15-30% yield advantage over inbred rice, increasing demand for hybrid rice especially in developing countries. Moreover, hybrid rice has also shown better performance under adverse conditions like drought and saline conditions. Therefore, multi-location trials need to be done before the hybrid rice promising genotype released as national varieties and passed on to farmers as end users. Varieties of hybrid rice developed in the plant breeding will eventually planted by farmers in various different environments. The results of multi-location trials of promising hybrid rice genotypes often reflects differences in grain yield in each location that the highest yield of a genotype in one location often showing is inconsistent in other locations. This is caused by the interaction between genotypes and environment, making it difficult for plant breeders in selecting the best genotype. Therefore, The G x E interaction is an important aspect of both plant breeding program and the introduction of new crop cultivars (Mc Laren and Chaudhary,6 Prasad and Sing7 and Freeman.8 Similarly, The AMMI model is a hybrid model involving both additive and multiplicative components of two way data structure which enabled a breeder to get precise prediction on genotypic potentiality and environmental influences on it. AMMI uses ordinary ANOVA to analyze the main effects (additive part) and principal component analysis (PCA) to analyze the non-additive residual left over by the ANOVA (Gauch17). The effectiveness of AMMI model has been clearly demonstrated by various authors using multilocation data in soybean,9 maize10 Wheat,11‒16 Field pea17 and rice,18 Das et al.,19 Tariku et al.,20; Nassir, 21; Islam et al.,22 Crop yield is a complex trait that is influenced by a number of component characters along with the environment directly or indirectly. Hence, if we could develop high yielding stable hybrid rice which adopted on diverse environments, to play a vital role in future food security of Bangladesh. The main objectives of the present study are to identify higher yielding promising hybrid rice genotypes having wide adaptation and/or specific adaptation to environment and environment interaction for their yield stability and adaptability across different environments.