[Analysis on the inheritance of inhibition and anti-inhibition of coleoptile purple line in rice and the SSR location of Ai(t) gene].

The ratio of purple line: no-purple line(13:3) was observed in six different F2 populations produced by crossing between parents with purple line and no-purple line in coleoptile. The backcross of XNA//XNA/ 21A150 (XNA, no-purple line and CMS, as the recurrent parent) resulted in a ratio of 1:1 (purple line: no-purple line). Genetic analysis showed that the expression of rice coleoptile purple line was influenced by two genes, inhibiting gene I and anti-inhibiting gene Ai(t). I gene inhibits P gene of C_A_P_ system and Ai(t) inhibits / gene, respectively. The gene pools of Ai(t) ai(t) and ai(t) ai(t) were constructed with BF1 of XNA//XNA/21A150. SSR analysis indicated that Ai(t) gene was linked with the markers of RM335, RM295, RM287 and RM21 and the genetic distance from Ai(t) to these four markers were 2.8 cM, 10.2 cM, 13.9 cM, 26.1 cM, respectively.

Characterization and mapping of a male-sterility mutant, tapetum desquamation (t), in rice.

A spontaneously mutated male-sterile material was found among the offspring of the indica restorer line Jinhuiyihao. To understand the status and function of the related gene and clone the gene, a near-isogenic line (NIL) of the male sterility was bred, and characterization of the mutant and gene mapping were performed. The results indicated that there are obvious differences between the male-sterile NIL and the indica maintainer line II-32B. The anther size of the NIL is smaller than that of II-32B, and the anther color is white in the NIL but yellow in II-32B. No pollen from the matured anther in the NIL was observed to be stained using KI-I2 solution. In transverse sections of the sterile anther, at early microspore stage the cytoplasm of the tapetum concentrates but the tapetum itself does not degenerate after microspores are released from the tetrads; the tapetum then desquamates from the anther wall and enwraps microspores; subsequently, the surrounded microspores collapse completely at late microspore and early bicellular pollen stages. Inheritance analysis showed that the male sterility was controlled by a single recessive gene, ostd (t). This gene was mapped between the SSR markers RM7434 and RM275 on chromosome 6, and the physical distance from RM7434 to RM275 is about 389 kb.