Contribution of IR20 and IR64 in Developing Three Bangladeshi Popular Rice Cultivars

Rice Breeding in Bangladesh started with establishment of Bangladesh Rice Research Institute (BRRI) in 1970. Itaimed at developing modern rice cultivars to benefit farmers. Among BRRI developed varieties, BR11 is considered as most popularTransplanted Aman cultivar having high yield (6.0 t/ha), bold grain and high amylose content. On the other hand, BRRI dhan28 andBRRI dhan29 are most popular Boro rice varieties for Irrigated areas. Because, they produce high yield across diverse rice growingareas. BRRI dhan29 is widely grown in haors where rice is grown once in a year. BRRI dhan28 and BRRI dhan29 accounted for 50%of total Boro rice areas. As a whole, the popularity of the cultivars BR11, BRRI dhan28 and BRRI dhan29 influenced subsequent ricebreeding trends and characteristics of new rice varieties. In this review, the pedigree information revealed that IR20 and IR5 acted askey foundation parents in developing the rice cultivar BR11 and BRRI dhan29. In contrast, same parental lineage of renowned IR64contributed in developing BRRI dhan28. The breeding history, agronomic traits, grain quality and molecular characteristics of abovecultivars have been discussed briefly. Thus, the background information generated from this review might help in developing breedinglines with higher genetic diversity, improved tolerance to biotic and abiotic stresses to obtain higher genetic gain from a breedingprogram. Furthermore, basic studies on these varieties and their important progenies might help to disclose the complex genetic controlof yield as well as other qualitative traits prioritized by farmers and consumers.