engleski

Pleiotropic effect of Rht3 dwarfing gene on some traits of wheat (Tr. aestivum L. em Thell)

During 17 years in continuous selection of heterozygous plants from cross 'Tom Thumb x Bankuty 1201' the true isogenic lines, differing only in the semi-dominant Rht3 dwarfing gene were developed. In the isogenic lines, the effect of double (Rht3 Rht3 = dwarf), single (Rht3 Rht3 =semi-dwarf), or no dwarfing gene (Rht3 Rht3 = tall) dosage on some plant, seed, and flour quality traits were observed during two years field experiment planted by 'honey-comb method' at Kri_evci, Croatia. Beside effect of environment, one of the reason, that reported results of other scientists often disagree in findings, could be frequent use of near-isogenic lines, and 'inter-cultivar' rather than 'inter-gene' comparisons. By using true-isogenic lines and 'inter-gene' comparison we hope to get more accurate results. Significant main effect of Rht3 gene was in shortening of plant height for about 54% and 28 % in double and single gene dosage respectively. Dwarf genotypes (Rht3 Rht3) had for12% more heads/plant, but the other yield components as number of grains/head, and grain weight/head was lower for 25 and 28% respectively, resulting for 27% significantly lower grain yield/plant. However, this could be a secondary side effect of five days prolonged vegetation influenced by doubled Rht3 gene also. There was no significant effect on flour protein content. Double gene effect was strong and significant for maximum dough viscosity measured by amylograph in BU (100%). In our environment full dwarf (Rht3 Rht3) has no agronomic value, but single gene dosage could be of interest in hybrid wheat breeding.

wheat - triticum aestivum; dwarfism; pleiotropic effect; yield components; grain yield; protein content; amylogram.

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