Genetic Effects on Grain Characteristics of indica Black Rice and their Useson Indirect Selections for some Mineral Element Contents in Grains

Complete diallel crosses with Oryza sativa L., six varieties of black rice and one variety of aromatic white rice were conducted to study the seed, maternal and cytoplasmic genetic effects on grain characteristics such as 100-grain weight, length, width and shape and their genetic correlations with Fe, Zn, Mn and P mineral contents in kernels by using the genetic model on quantitative traits of seed in parents and their F1s and F2s. The seed genetic effects were found more important than the maternal genetic effects for grain characteristics, and seed additive effects constituted a major part of their genetic effects. The heritabilities of seed effects were high for 100-grain weight, width and shape and moderate for grain length. Single seed selection based on the 100-grain weight, width and shape was advocated in early generations, whereas single plant and seed selection based on grain length were advocated in late generations. Significant genetic correlations including seed additive, dominance, cytoplasmic, maternal additive and dominance between 100-grain weight, length, width and shape and Fe, Zn, Mn and P mineral contents were observed. Indirect selection of grain characteristics may be one of the breeding methods to select for higher contents of Fe, Zn, Mn and P in black pericarp indica rice.