Correlation between polyovules and number of pistil lobes (stigmatic rays)in sugar beet (Beta vulgaris L.)

The polyovules phenomenon in sugar beet has the same importance for breedin g as multigermity, because only mono-ovulic monogerm plants can be used for mechanized cultivation. The polyovules trait was investigated in two Japan ese lines, mono-ovulic line NK-219-O and polyovulic line NK-183-cms. Plants of the former had three pistil lobes (stigmatic rays) in each flower, a si ngle ovule per ovary, a single seed in the mature fruit and a single seedli ng germinated in subsequent tests. Plants of the latter had 5-6 pistil lobe s in each flower, 2-3 ovules per ovary, double-seeds and double-seedlings. The correlations between a Pistil Lobes Index (PLI) and the number of ovule s per ovary, percentage of double-seeds in an X-ray test, and percentage of double-seedlings in germination tests were 0.885, 0.838, and 0.749, respec tively indicating close associations. These results are important both in s ugar beet breeding for indirect selection to eliminate the undesirable poly ovules trait and for botanical investigations of the relationship among dif ferent parts of the gynoecium.