Date of Award

1980

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

Polycross progeny tests and comparisons of advanced seedlings (cultivars) were conducted in 1978 and 1979 to determine the genetic variance, heritability and correlations of several characters in the sweet potato, Ipomoea batatas, L. In 1978, 41.8% of the 'L0-323' polycross seedling progeny had copper or rose skin colors and 2.4% had root yields higher than the highest yielding parent plants. In the 1979 polycross progeny test, estimates of heritability for root skin and flesh color were both very low. Root skin color was positively correlated with yield of US #1 roots, total yield of fleshy roots, vine length, and vine diameter but it was negatively correlated with vine color. Root flesh color was positively correlated with internode length and it was negatively correlated with yield of US #1 roots, total yield of fleshy roots, plant production, vine diameter, and number of branches. The estimates of heritability for yield of US #1 roots and total fleshy roots indicated that selection could be practiced on an individual plant basis. Both the yield of US #1 and total fleshy roots were positively correlated with vine length, vine diameter, internode length, and number of branches. Total fleshy root yield was positively correlated with leaf shape while yield of US #1 roots was negatively correlated with vine color and leaf vein color. Progeny mean for weight loss in storage was lowest for 'L9-163'. Its genetic variance component was a negative value and its correlation coefficients with other characters were not significant. For plant production, heritability was very low and it was negatively correlated with root flesh color. Vine length, vine diameter, young foliage color, leaf shape, and petiole length had high estimates of genetic variances with heritability values of over 0.50. Vine color, internode length, number of branches, and leaf vein color had lower than 0.21 heritability values. Comparisons of advanced seedlings in 1978 showed that 'L4-62' and 'L5-36' had comparable US #1 root yields with 'Centennial' in total marketable roots, 'L0-323' had a comparable yield with 'Centennial'. 'L4-112' produced the highest yield of US #2 or canners grade roots, and it produced the largest number of total marketable roots. In 1979, 'L0-323' and 'L4-62' produced the highest yields of US #1 roots, Jumbo roots and total marketable roots. 'L3-186' and 'L4-131' had the highest dry matter content among the advanced seedlings but lower than 'Porto Rico'. 'L5-150' and 'L4-131' had the least weight loss in storage at 60(DEGREES)F (15.5(DEGREES)C) and 'L5-36' had the least weight loss at 70(DEGREES)F (21.1(DEGREES)C). As an average of cultivars, weight loss at 70(DEGREES)F (21.1(DEGREES)C) storage was higher than weight loss at 60(DEGREES)F (15.5(DEGREES)C) storage both in 1978 and 1979 tests. Organoleptic ratings for baked roots in 1978 showed that 'L0-323', 'L4-112' and 'L4-131' had comparable baking indices at 60(DEGREES)F (15.5(DEGREES)C) and at 70(DEGREES)F (21.1(DEGREES)C). Generally all the cultivars were considered acceptable in quality factors in 1978 and 1979 tests. Dry matter content was positively correlated with flavor of baked roots at both storage temperatures in both 1978 and 1979 tests. Plant production tests in 1978 and 1979 showed that 'Porto Rico' and 'L4-112' produced the largest number of plants per bushel of roots stored at 60(DEGREES)F (15.5(DEGREES)C) and 70(DEGREES)F (21.1(DEGREES)C). All cultivars stored at 70(DEGREES)F (21.1(DEGREES)C) produced an increase in plant number over the 60(DEGREES)F (15.5(DEGREES)C) storage.

Pages

155

Share

COinS