Heterosis and ion transport in hexaploid varieties of rye‐wheat (triticale) compared to the parental species

Abstract

Listen

Translate article

Important winter and spring varieties of hexaploid rye‐wheat (triticale cvs. 6048 and 5004) were selected for study of heterotic effects on growth and ion transport in the hybrids compared to the parental species rye (Secale cereale L. cvs. MT 77 and Sv 6970) and wheat (Triticum aestivum L. cvs. Starke II and Sonett). After 3 days germination, seedlings were grown 11 days in water culture on a complete nutrient solution diluted to 1, 25 and 50%. Intracellular influx and transport to shoots of K+, Ca2+, sulphur and phosphate were determined by using radioactive tracers (86Rb (for K+), 45Ca, 35S and 32P). Varietal differences in the parameters studied were generally small compared to differences between species. The heterotic effect on growth of rye‐wheat was mainly localized to the shoots at high ionic strengths (25% and 50%). There were no heterotic effects on ion influx or transport to the shoots. Ion influx and transport characteristics in rye‐wheat appear to be inherited mainly from wheat. Growth of all species on 1% medium was severely reduced. At the low ionic strength ion influx was inhibited similarly for all species, except influx of K+ (86Rb) which was higher in rye‐wheat and wheat than in rye. Ion influx and transport in rye‐wheat and wheat and in rye differed especially for 25% and 50% media. Rye had the highest ion influx and transport and the highest shoot/root fresh weight ratio at the high ionic strengths. To feed a comparatively large shoot, rye may compensate for a relatively small root system by efficient ion transport mechanisms.