Distribution of the Classification Traits in the F2 Progeny of Two Crosses of indica／japonica in Rice （Oryza sativa）

Comparison of seed setting rate, plant height and Cheng‘s morphological traits were made between the F2 progeny of indica-japonica hybrids, 02428/Pei‘ai 64 and Taichung 65/Teqing. There existed resemblance normal distribution in plant height, and the distribution had no relationship with the seed setting rate and plant height in F1 progeny, suggesting that there were no gametic selection for the plant height in the F2 progeny of indica-japonica hybrids. An average seed setting rate of the F2 was equal to the F1 populations in the recombination of 02428/Pei‘ai 64 in which there was an excellent cross compatibility, but the remarkable increase in the seed setting rate from the F1 to F2 in Taichung 65/Teqing, indicating that gametic selection only took place in the indica-japonica crosses with low cross compatibility while null or little in the hybrids with high compatibility. There were many intermediate types among the leaf pubescence, color of hull at heading, and length of the first and second panicle internode, and these Cheng‘s morphological traits was distributed normally; there were also a little intermediate types in hull hairness and phenol reaction with bi-peak distribution; while length to width ratio of grain was inclined to the japonica types obviously showing a skewed distribution in the Fz population. Although Cheng‘s morphological traits in F2 populations had inconsistent distribution types, Cheng‘s morphological traits index showed normal distribution, which suggested that intermediate types, i.e. indicalinous or japonicalinous, were primary in F2 population.

Distribution of the Classification Traits in the F2 Progeny of Two Crosses of indica/japonica in Rice (Oryza sativa)

Comparison of seed setting rate, plant height and Cheng's morphological traits were made between the F2 progeny of indica-japonica hybrids, 02428/Pei'ai 64 and Taichung 65/Teqing. There existed resemblance normal distribution in plant height, and the distribution had no relationship with the seed setting rate and plant height in F1 progeny, suggesting that there were no gametic selection for the plant height in the F2 progeny of indica-japonica hybrids. An average seed setting rate of the F2 was equal to the F1 populations in the recombination of 02428/Pei'ai 64 in which there was an excellent cross compatibility, but the remarkable increase in the seed setting rate from the F1 to F2 in Taichung 65/Teqing, indicating that gametic selection only took place in the indica-japonica crosses with low cross compatibility while null or little in the hybrids with high compatibility. There were many intermediate types among the leaf pubescence, color of hull at heading, and length of the first and second panicle internode, and these Cheng's morphological traits was distributed normally; there were also a little intermediate types in hull hairness and phenol reaction with bi-peak distribution; while length to width ratio of grain was inclined to the japonica types obviously showing a skewed distribution in the F2 population. Although Cheng's morphological traits in F2 populations had inconsistent distribution types, Cheng's morphological traits index showed normal distribution, which suggested that intermediate types, i.e. indicalinous or japonicalinous, were primary in F2 population.