Studies cn the growth habit of wheat varieties . : 2. Relation of thermo-effect and photoperiodism and its effect on the growth habit of wheat varieties.

Abstract

The authors decided the 3 genes affecting the growth habit of wheat in previous report. Among these 3 genes, E factor determines erect-type, both P and T factors control prostrate-type, but differ in their effect on prostrate as clarified in report l. In this paper, we clarified following points, changes in growth .habit, development of plant height, variation of heading dates in 4 experimental plots, control, long day, short day (10 hours) and glass house culture. Results obtained are briefiy summarized as follows : 1. Varieties having the E-gene affecting the erect-type are not aff6cted fcr growth habit, development of plant height and heading date by temperature and short day treatment. 2. Between the 2 genes (P, T), varieties containing the P factor affecting the prostratetype showed remarkable effects by temperature. So P factor seems to have intimate relation to thermo-reaction. 3. Change in growth habit, plant height and heading date, was increased by long day and decreased by short day in the varieties having the T gene controlling the prostratetype. So the gene T seems to have deeper relationship to photoperiodism. 4. Both P and T genes affecting the prostrate-type were observed having the intimate relationship to both thermo-effect and photoperiodism.