Characteristics And Application Of The Thermo/Photoperiod-Sensitive Genic Male Sterile Rice Line Yutu S Labeled With Green-Revertible Albino Leaf Marker

The discovery of thermo/photoperiod-sensitive genic male sterile (T/PGMS) lines opened a new avenue for developing two-line hybrid rice system. Although many T/PGMS lines were successfully released, only a few T/PGMS lines turned out to be of commercial use due to the instability of the male-sterility. For the most T/PGMS lines, they become partially fertile when a dramatic change in weather occurs during male-sterility-inductive period, the resulting hybrid seeds could be contaminated by the T/PGMS seeds. This problem has become a major obstacle of two-line hybrid rice system. A novel type of T/PGMS rice line Yutu S labeled with green-revertible albino leaf color marker was developed from the leading T/PGMS indica rice line Pei'ai 64S dry seeds eradiated with 300Gy 60Cobalt gamma rays and then continuously selected. The genetic control, mutant gene mapping, agronomic traits, fertility characteristics, combining ability, grain quality, disease resistance of the green-revertible albino leaf color marker, and its potential application in simple determination of seed purity and efficient false-elimination were systematically investigated in the current paper.The green-revertible albino leaf marker is of a marker developmentally expressing albino leaves and characterized by significantly worse growth at the 1-3 leaf stages in compassion with that of the wild type Pei'ai64 S. The albino leaves commence to be greenable after extension of the 4th leaf and recover to the normal green at the 6th leaf stage. The major agronomical characters, fertility characteristics, combining ability, disease resistance, and gra in quality of Yutu S were similar to that of Pei'ai64 S in the mature plant. Genetic study indicated that the mutated green-revertible albino (gra) leaf color trait was controlled by a single recessive gene located on the short arm of chromosome 10. The SSR marker RM590 is closely linked with the gra gene, and the genetic distance is 2.5 cM. Physiological compensation mechanism analysis showed that an increase in the activity of adenylate and ribulose-1,5-bisphosphate carboxylase was observed in the chloroplast of T/PGMS line Yutu S during the tillering, booting, and flowering stages. With this novel T/PGMS rice strategy, it is feasible to develop an effective system for early rapid determination of seed purity in the laboratory. When this technology is employed in hybrid rice production, it could be used as a screening marker for facilitating the identification of off-type green seedlings in the production of hybrid rice and multiplication of the T/PGMS parent. Most important of all, it can ensure field seed purity via auto-elimination of the contaminated self-pollinated T/PGMS seeds based the weaker growth of albino seedling.