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  • Author or Editor: E. W. Hellman x
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Abstract

A microcomputer program was written to enable the development and calculation of a selection index appropriate for the objectives of any plant breeding program. Other features of the computer program include the capability to accept numerical character rating scores and statistically analyzed objective measurements, estimate missing data, average multiple year data, and storage of breeding line data with output capability.

Open Access
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Abstract

Cultivars of 5 highbush (Vaccinium corymbosum L.) and 5 rabbiteye (Vaccinium ashei Reade) blueberries were each pollinated with a series of cultivars of varying genetic relationship. A significant reduction in mean berry weight was associated with an increase in the degree of relationship between parents for one highbush and one rabbiteye cultivar. The mean number of seed per berry was significantly reduced and was associated with an increase in the degree of relationship for 3 highbush and 2 rabbiteye cultivars. Level of inbreeding did not affect percentage seed germination. Two highbush cultivars demonstrated a significant reduction in mean seedling fresh weight associated with an increase in the level of inbreeding. Rabbiteye seedling vigor data were insufficient to draw any conclusions on inbreeding effects. Variability of cultivars in response to cross-pollination among related individuals suggests that other factors may be more influential in some instances.

Open Access

Abstract

The discrepancy in seed set observed in reciprocal crosses of red (Rubus idaeus L.) and black (R. occidentals L.) raspberries verifies unilateral incompatibility. The strength of the incompatibility varies between cultivars; some red × black crosses yield a small percentage of seed set by simple cross-pollination, while others produce almost no seed. Although black cultivars have shorter pistils than red cultivars, the role of this factor in incompatibility is unknown. Bud pollination and heat treatments increased seed set in some normally incompatible red × black crosses.

Open Access