GENETIC-ASPECTS OF STARCH GRANULE TRAITS IN BARLEY

Starch, the main constituent of barley (Hordeum vulgare L.) kernels, i s accumulated as granules classified as large, Type A, and small, Type B. The objectives of this research were to assess the importance of g enotype and environment in determining starch granule morphology to es timate heritability for these traits, and to investigate the associati on between granule traits and malting quality. Fourteen genetically di verse barley genotypes were evaluated in four environments, and four p opulations were evaluated in a parent-offspring study. Data were obtai ned using digital image analysis of starch granules. Significant diffe rences were found among the 14 barley genotypes for five of six granul e traits. Environment had a significant effect on four granule traits, but genotype by environment interactions were not significant. Type-A granules accounted for 94% of total starch by volume, with a range of 92 to 96% for the 14 genotypes. Genotype means for A granule volume r anged from 1720 to 2164 mu m(3) and for surface area, from 773 to 944 mu m(2). On the number basis, the small B granules accounted for 93% o f all granules in the 14 genotype set. Malting and six-row genotypes h ad larger A-granule surface area and volume than feed and two-row type s, although some overlapping of genotypes occurred. There was little e vidence of association between starch granule morphology traits and ma lting quality traits. Heritabilities were encouraging on a genotype me an basis in the 14 genotype study, but were low in the parent-offsprin g heritability evaluation. It appears that greater genetic variability in granule traits is needed before considering selection for starch g ranule traits to improve grain quality.