34. Maternal effect on chalkiness in rice kernels

To evaluate the effect of maternal parents on chalkiness of rice kernels in F\1\ and other hybrid generations, 12 crosses were made between Indica varieties differing in chalkiness, and two of them were studied with regard to F\2\ and B\1\ generations, as follows:

The plants for test were grown in the field, and at maturity the translucency of rice kernels from each plant was tested by using a digital photoelectric instrument for chalkiness developed by Zhejian Academy of Agricultural Sciences. The instrument measures light transmission rate (T) in values 0 to 1, so that chalkiness is shown by C=1-T. The conventional white belly, white core and white back grades 0,1,5 and 9 proposed by IRRI (1980) correspond to C values <0.2, 0.2-0.25, 0.25-0.35 and 0.35<, respectively.

The F\1\ plants from reciprocal crosses showed significant differences in chalkiness when the parental difference reached a certain extent, and the kernels produced by an F\1\ plant were less chalky when the female parent was less chalky. But there was no significant reciprocal difference when both parents were highly chalky (Table 1). Among the kernels produced by an F\1\ plant, no visible differences in chalkiness were found, contrary to the observations of Yang et al. (1986). A number of variants exceeding higher parent in chalkiness were observed in two F\2\ populations when the female parent had higher chalkiness (Fig. 1). When the F\1\ used as female was backcrossed to less chalky parent, the distribution of chalkiness in the B\1\ populations suggested that the variation in chalkiness was influenced strongly by the female parent. Thus, the expression of chalkiness in hybrid progenies is influenced by the female parent. For improvement of chalkiness, less chalky varieites should be chosen as the female parent.

Table 1. Reciprocal differences in chalkiness of kernels produced by F\1\ plants between parents differing in chalkiness

Yang, Rencui, Kangjieng Lian and Qinghua Chen, 1986. Xenia of chalkiness in rice and the genetic analysis of chalkiness of hybrid rice. J. Fujian Agric. College 15(1): 51-54.