The modification of `the nearest neighbour' method for using various size plots in field trials has been developed and the results of testing its validity by computer simulation are presented . It was found that the Field-S variant of this method using a square pilot area is the best for fields with a low and medium spatial heterogeneity . The Field-L variant using the least quantity of neighbours, offers advantages for fields with a medium and high spatial effect .The optimal values of the controlling coefficients of these variants were computed to allow for the calculation of the environmental indices over a wide interval of spatial heterogeneity with sufficient accuracy . For this reason, this local adjustment method is recommended as an obligatory statistical procedure for a prior data analysis of any field experiments that have fulfilled the necessary requirements . The original Field and CRBSD programs using the local adjustment method developed have been created for IBM-compatible personal computers .
Presented are the results of an application of the local adjustment Field-method in the analysis of the real field experiments without replications and in experiments with pseudo-and random replications . It was found that the local adjustment allowed a more precise estimation of the real values of genotypes in all kinds of experiments over a wide interval of spatial heterogeneity . The results obtained indicate that by simply using up to 5 random replications the decrease of the spatial effects is inadequate for fields with medium and high soil heterogeneity or with unsuccessful randomization . The Field-method which has sufficient precision in evaluating spatial heterogeneity, considerably increases the reliability of estimates in experiments even with a small number of replications or with unsuccessful randomization. Therefore, for all field experiments that have fulfilled the necessary requirements the Field-method is recommended as an obligatory statistical procedure for a prior data analysis as it allows an accurate estimation of the real character expression of genotypes, as well as the random variance in experiments without replication and the parameters of ANOVA in ones with pseudo-and random replications.
A method to estimate variety value directly in a plant breeding process is proposed. The approach is based on frequencies of variety progenies succeeding in breeding trials. The number of crossing combinations is demonstrated to estimate parental breeding values (PBV) more effectively than the number of lines. Because of the possibility of significant sexual effects the parental breeding value is estimated by the square mean of the female and male variety breeding values. For adequate PBV estimation, all the varieties tested should involve an equal number of crossing combinations as male and female parents. The Latin square principle can be used for planning such crosses. The results of barley breeding programmes are used as an example for the application of the proposed method. It is shown that the PBV estimates obtained in a current breeding cycle allow the effectiveness of the following cycles to be increased by better planning of the subsequent crosses.
SummaryFunctional female fertility (FFF) and functional male fertility (FMF) were studied in diploid potato clones, including S. tuberosum haploids, F 1 hybrids between haploids and other Solanum species, and in progenies from subsequent hybridisations. The results of 402 crosses between 91 diploid potato clones revealed that 60% of all genotypes had low levels of FFF as well as low levels of FMF regardless of their origin and degree of hybridity. Failed crosses (without any fruits at all) and those with a low level of success (with less than 3 s6eds per pollinated flower) constituted 69% of all studied crosses. Most of these had resulted from parents with low levels of FFF and FMF, and these two characteristics were expressed independently. Functional female fertility affected crossability behaviour no less than FMF, therefore both FFF and FMF should be controlled in diploid potato clones involved in breeding. Reliable FFF and FMF estimates can be based only on crossing results. The coefficient of multiple correlation between seeds per pollinated flower in crosses and FFF and FMF estimates of the parental clones was 0.80 (P<0.01). Hence the compilation and analysis of the results of diploid potato crosses allow a reliable assessment of FFF and FMF and consequently the prediction of crossability with a degree of sufficient accuracy.
An analysis of genetic heterogeneity was performed for two populations of Ophrys insectifera L. located in the Berezinsky Biosphere Reserve and the Verkudy village. The species are critically endangered (CR). The analysis of data obtained using iPBS markers detected the higher risk of extinction of the population in the Berezinsky Biosphere Reserve than the population from the Verkudy village, since the level of population genetic heterogeneity from the Verkudy is higher compared to the Berezinsky Biosphere Reserve. Molecular variance analysis (AMOVA) and other parameters of genetic variation showed the major fraction of intrapopulation variation (64 %, Gst = 0.26). Principal Coordinates Analysis (PCoA) revealed two groups that coincided with natural populations, and confirmed a larger genetic heterogeneity in the population from the Verkudy.
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