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Naked oat refers to a variety of Avena sativa with lemma and palea separating from the grains. Its spikelets are multiflorous and morphologically different from the husked oat. Problems with preharvest sprouting, threshability, rancidity, a wide range of kernel sizes, as well as its relatively low tolerance to limited soil water content, are its main drawbacks. Nevertheless it could be an alternative to a conventional oat. Unfortunately, its genetic variation is still poorly recognized. In the given study a set of 26 naked oat cultivars and lines were analyzed with 25 inter-simple sequence repeats (ISSR) primers that amplified as many as 429 DNA fragments among which 204 were polymorphic. The average number of markers amplified per primer pair and polymorphism information content (PIC) value equaled to eight and 0.23, respectively. Forty four unique PCR products were identified for different genotypes. While Unweighted Pair-Group Method with Arithmetic Mean failed to distinguish the materials into main clusters it demonstrated that cultivars 'Akt', 'Polar', 'Cacko', 'Siwek', 'Nagus' and most of the DC lines were within a single group. Moreover, the cultivars that were closely related based on their breeding pedigree (related to 'Akt') were close to each other. Principal Coordinate Analysis explained 54.1% of variance and was in good agreement with the UPGMA. ISSR markers could be used for the evaluation of genetic similarity of cultivars and lines as well as the differentiation of individual genotypes. This study demonstrated that the available A. sativa naked type genetic pool is relatively wide and have the potential for further breeding progress.

The purpose of the paper was to determine phenotype and genotype variability of yield components structure (number of grains, grain mass and 1000 grain weigh) as well as of the basic technological traits (sedimentation number, falling number, protein percentage content per grain). The research also considered the issue of pre-harvest sprouting. During each vegetation season rainfall and temperature were recorded. The examined material were the strains of F6 - F7 generation. Coefficients of correlation between the values of particular traits and mean temperatures and rainfall sum during a given season showed that yield component parameters were significantly modified by temperature; whilst warm vegetation seasons proved to be beneficial. Negative correlation between the rainfall sum and the number of grains and grain mass as well as 1000 grain weight suggests that the excess of water may be more detrimental for the yield than its shortage. Coefficients of correlation between the values of basic technological parameters and mean temperature were negative and not very high or low or even – insignificant, as in the case of falling number. High h2 coefficients suggest a good heritability of yield components parameters, and yield per ear seem to be the trait that was transmitted best. Amongst the basic quality indicators, the highest heritability was observed in the case of falling number and the lowest one in the case of sedimentation number. The weakest genetic conditioning was observed in the case of resistance to sprouting, measured as the percentage of sprouting grains in the ear. It seems therefore that genetic variability was, to a large degree, masked by the environmental impact and, in spite of a high degree of genetic conditioning, the effectiveness of selection based on a visual evaluation of the forms rated for further cultivation might be limited.

One of the main problems in plant breeding is the selection of the best genotypes. Most often the selection is made using yield as a main trait of continuous type, and ignoring the other traits of discrete type. Here, a simple procedure is proposed for dealing with the selection problem using not only the yield, but also an auxiliary discrete trait. The method is based on transforming the continuous variable into a discrete one and testing the dependence of variables with the use of contingency tables. The procedure is illustrated by a real unreplicated experiment with winter wheat.