Starch is the main component of cereals like rice. It is mainly composed of amylose and amylopectin. Apparent amylose content (AAC) in rice grain controlled by granule bound starch synthase enzyme (GBSS) is the key factor determining cooking and processing quality. The present study has been attempted to decipher the genetic variability among 36 cultivars of rice for agro-morphological parameters along with AAC and amylopectin content, to determine the extent of association among yield and its contributing characters and to detect the sequence variations among the cultivars having differential AAC. Results revealed the presence of adequate genetic variability among the tested rice cultivars for yield attributing traits, as well as their AAC and amylopectin content. Most of the yield attributing traits was under control of additive genes. Genetic diversity study of the tested rice cultivars grouped them into four clusters. The nucleotide sequence and derived amino acid sequence variations among the region spanning between the intron 7 and exon 10 of GBSSI allele from the rice cultivars differing in AAC detected the presence of several SNPs, deletions and insertions within the tested exon and intron regions. Presence of methionine (M) or isoleucine (I) at 308 aa position and presence of phenylalanine (F) at 425 or 434 aa position of GBSSI protein across the tested rice cultivars can be exploited in marker-assisted breeding programme for developing high yielding rice cultivars with proper grain quality as per consumer’s preference.

淀粉是大米等谷物的主要成分。它主要由直链淀粉和支链淀粉组成。由颗粒结合淀粉合酶（GBSS）控制的米粒表观直链淀粉含量（AAC）是决定蒸煮和加工品质的关键因素。本研究试图破译 36 个水稻品种的农业形态参数以及 AAC 和支链淀粉含量的遗传变异性，以确定产量及其贡献性状之间的关联程度，并检测具有差分 AAC。结果表明，受试水稻品种之间存在足够的产量归因性状遗传变异性，以及它们的 AAC 和支链淀粉含量。大多数产量归因性状受加性基因的控制。受试水稻品种的遗传多样性研究将它们分为四个集群。跨越内含子 7 和外显子 10 的区域之间的核苷酸序列和衍生的氨基酸序列变异来自具有不同 AAC 的水稻品种的GBSSI等位基因检测到在测试的外显子和内含子区域内存在几个 SNP、缺失和插入。在所测试的水稻品种中，GBSSI 蛋白的 308 aa 位置存在甲硫氨酸 (M) 或异亮氨酸 (I)，而 GBSSI 蛋白的 425 或 434 aa 位置存在苯丙氨酸 (F)，可用于开发高产水稻的标记辅助育种计划根据消费者的喜好选择具有适当谷物质量的品种。