HEREDITARY CONTROL OF CALLUS FORMATION IN MAIZE ENDOSPERM CULTURED IN VITRO

Abstract

Four inbred maize strains, S41, S42, S43, and S44, which were mutally unrelated in their genetic background, and differed from each other either in color of aleuonr or in starch property of endosperm, (yellow starchy, purple starchy, white waxy, and yellow sugary) were cultured on white''s medium supplemented with yeast extract. Plants of each strain were self-pollinated or crossed with plants of other strains. Endosperm tssues were excised from kernels of each ear 6 to 15 days after pollination. Callus formation was observed only in endosperm explants from the starchy strains (S41 and S42). Excised endosperm tissues of F1 kernels obtained by the reciprocal crosses between S41 and S42 showed a better growth in vitro than those of either of the Inbred parents. Progeny tests of the S41 X S42 hybrid suggested that the 2 strains could be different in 2 or more genetic factors concerning callus formation in the endosperm explant, although the phenotype expression is influenced by environmental and nutritional factors. The waxy strain S43 may possess a genetic factor for inhibiting callus formation.