No abstract

The Endosperm Balance Number (EBN) and the polar-nuclei activation (PNA) hypotheses have been developed to interpret, explain and predict interspecific and interploidy crossabilities in the Solanums and the Gramineae, respectively. Although these two hypotheses evolved independently, they share a number of common features. Assignment of EBNs and 'activation/response values' (AVs/RVs) depend on plumpness, size, and germinability of hybrid seeds. Also, both hypotheses emphasize the importance of a balanced parental genic contribution for the normal development of endosperm. However, in the EBN hypothesis a 2 maternal∶1 paternal EBN ratio is a prerequisite for successful interspecific crossability, while the PNA hypothesis is based on the stimulative strength of the male nuclei to initiate mitotic divisions in the primary endosperm nucleus and is idependent on a 2∶1 ratio between the RV of the polar nuclei and the AV of the male gamete. Differences and similarities betweeen the EBN and PNA hypotheses are summarized and contrasted. It is proposed that EBN and PNA be considered as the same concept.

Correlations among several chemical and agronomic characteristics were determined in 1970 and 1971 for 10 Avena sativa L. cultivars and for 46 F4‐F6 backcross “N” lines derived from a complex interspecific cross involving a 6x amphiploid. In 1971, groat protein percentage was significantly and negatively correlated with yield in both series, but in 1970 a nonsignificant positive r of 0.37 existed in the A. sativa series. A strong negative association existed between groat protein percentage and kernel weight in the A. sativa and 46 “N” line series in 1971 (−0.71** and −0.28*, respectively), when kernel weights were considerably higher than in 1970. Correlation coefficients between groat protein and lipid percentages were negative, though nonsignificant, for the A. sativa series in both years, but were near zero or positive in the “N” series. ‘Dal’ was high in both groat protein and lipid percentages, illustrating that departures from the general relationship exist. Lines such as ‘Lodi,’ with higher lipid and lower protein percentages, contribute strongly to a negative association.The correlation between lipid percentage and grain yield was significant and positive only in 1971. While r values between lipid percentage and kernel weight were significantly positive in the A. sativa series in both years, the relationship in the “N” series was significant and negative in 1970 and near zero in 1971. Groat protein percentages varied more from year to year within selections than did lipid percentages.The association between groat protein percentage and four of the six fatty acids differed in the A. sativa series from that in the “N” series. The relationship between lipid percentage and the fatty acids were considerably more in agreement for the two series. Lipid percentage was positively associated with percentages of stearic and oleic acids, but negatively correlated with myristic, palmitic, and linoleic acids.

No abstract

Oil and protein relations in oat groats were studied with location‐year data from the USDA‐coordinated Uniform Early and Midseason Oat Performance Nurseries. Ranges, means, and correlations between protein and oil in oat genotypes were calculated (i) by location and across genotypes, (ii) by genotype and across locations, and (iii) by genotype and location and across years. Of 277 correlations calculated, only 36 were significant at the 5 or 1% level, and 20 of these occurred in comparison (iii). A majority of the correlations were positive in comparison (i) but, conversely, were negative in comparisons (ii) and (iii). A possible cause of these contrasting results is a blending of relationships in comparison (a) because of the independence of protein and oil levels in the many genotypes compared on a location basis. Within an individual genotype across locations (comparison b) and in specific locations (comparison c), changes in concentration of one seed component probably were associated with changes in concentration of other components (negative correlations).Variation among oil concentrations generally was less than that among protein concentrations because of the greater effect of environment on protein. Homogeneity of variance ratios (protein/oil) were greater in comparison (b) than in comparison (a). Variation in protein and oil concentrations among oat genotypes provides breeders with great latitude in pursuing their goals.