18. Linkage relationship of long palea in rice

Rajendra Agricultural University, Bihar Agric. College, Sabour, Bhagalpur, India

Rao and Misro (1968) reported a floral variant of rice, long palea, where palea invariably outgrows the lemma. It was found to be due to dominant complementary genes. The second report on the occurrence of long palea was by the author (Thakur 1971). In an F\2\ of a cross between two normal palea varieties, Ac 1224 and 7107 (a marker type, received from Mr. N. E. Jodon of U.S.A.) plants with long palea were obtained. This long palea was found to be a recessive trait. All F\3\ progenies raised from long palea F\2\ plants bred true. The F\1\ plants of long palea and normal palea parents had normal palea and the F\2\ segregation confirmed its recessive nature. A gene symbol lp was suggested.

This gene was found linked with g (extra-sterile glume) of linkage group IV (Thakur and Roy 1975). In order to clearly establish its linkage relationship, five long palea lines were crossed with representative markers of three linkage groups. Long palea segregated independently of Cl (clustered grains) and C (Chromogen gene) of group I, pl (purple leaf), lg (liguleless) of group II and Rd (red pericarp) of group III. In the F\2\ of a cross between 7435 and Ext. 20-4 where long palea and rolled leaf segregated in coupling phases, linkage between long palea and rolled leaf, rl was observed. The X² value (72.6) for independent segregation was highly significant and crossover value between these two markers was 11.8%.

The new linked genes (lP and rl) are tentatively assigned to group IV due to earlier report of linkage between lp and g. The allelic relationships of this rl gene with other rl genes reported earlier in Japonica rice need to be investigated.

Rao, A. S. and B. Misro, 1968. Linkage studies in rice, Oryza sativa L. VIII. Inheritance of genes governing long palea, red pericarp, grain shape and shattering of grains and their relationships. Oryza 5: 5-9.

----- and R. P. Roy, 1975. Linkage studies in indica rice, Oryza sativa L. Euphytica 24: 511-516.