engleski

Estimation of quantitative genetic parameters for pre-harvest sprouting resistance in wheat under laboratory and field conditions

Pre-harvest sprouting in wheat can cause a reduction in yield, test weight and grain quality creating large financial losses to producers. Tolerance to pre-harvest sprouting is therefore a desirable trait of a cultivar in conditions of rainy weather before harvest. The objective of the present study was to estimate variance components and heritability of resistance to pre-harvest sprouting in wheat under field and laboratory conditions. Field trials including 25 winter wheat varieties were conducted during three successive growing seasons in total of eight environments (location-year combinations) following a randomized block design in two replications. Pre-harvest sprouting resistance of the studied varieties was estimated by measuring the level of dormancy in laboratory germination tests with threshed grains, whereas field sprouting damage was estimated by the Hagberg falling number (HFN) test as well as by the percentage of sprouted grains in the field (field sprouting). All tests were conducted on samples taken at harvest ripeness (Time 1) and 14 days after harvest ripeness (Time 2). The environmental component of variation accounted for 1 to11 % of the total variance for laboratory germination tests. For HFN test it accounted for 28% and 70% for Time 1 and Time 2, respectively, and for field sprouting it accounted for 52% of the total variance. The proportion of the genetic component of variance in the total variance ranged from 65% to 83% for germination tests and from 15% to 40% for HFN test, whereas it accounted for only 7% of the total variance for field sprouting. The magnitude of genotype x environment (G x E) variance was similar for germination tests and the HFN test (10 -16% of the total variance) whereas G x E variance for field sprouting accounted for much higher amount to the total variance (35%). Heritability estimates on an entry mean basis varied from 0.96 to 0.98 for germination tests, from 0.90 to 0.93 for HFN tests and was only 0.61 for field sprouting. Phenotypic correlations among tests varied across environments.

wheat; pre-harvest sprouting; heritability

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