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Comparison Of Mass Selection And S1 Testing Recurrent-Selection Methods In Sorghum, R. E. Secrist, R. E. Atkins

Journal of the Iowa Academy of Science: JIAS

Mass selection and S₁ testing are often used for the improvement of sorghum [Sorghum bicolor (L.) Moench] populations. Both recurrent selection methods have a place in applied breeding programs and should be used where they are likely to be most advantageous. S₁ families of a random-mating sorghum population mass selected three cycles (C3) for individual-panicle weight [IAP1R(M)C3] were compared with S₁ families from a population (C3) advanced from the same base (CO) population by using replicated yield tests in each cycle [ IAP4R(S₁)C3]. Our objectives were to compare the performance in C3 of families developed …

Estimates Of Quantitative Genetic Parameters M Iap2b(M) Random-Mating Sorghum Population, A. J. Maves, R. E. Atkins

Journal of the Iowa Academy of Science: JIAS

Random-mating populations of sorghum [Sorghum bicolor (L.) Moench] are used extensively as germ plasm in the development of parental lines for hybrids. Populations improved by recurrent selection provide a useful source for the selection of superior parental lines. Our objective was to determine the effectiveness of mass selection for threshed-panicle weight by comparing the performance of lines (S₁ families) chosen randomly from CO and C4 of sorghum population IAP2B. Sixty S₁ families from each cycle were grown in five Iowa environments.

Four cycles of selection for panicle weight shifted the mean for grain yield favorably, and the range …

Hybrid Performance Of Sorghum Parental Lines Developed By Mass Selection And S1 Yield Testing, K. R. Ess, R. E. Atkins

Journal of the Iowa Academy of Science: JIAS

Experiments were conducted co obtain information on the effects of two methods of developing parental lines from a random-mating population of sorghum (Sorghum bicolor L. Moench) on hybrid performance. Gridded mass selection for threshed panicle weight was used in developing IAP1R(M)C3: and a sister population, IAP4R(S1)C3, was advanced each cycle on the basis of grain yield of S₁ families in replicated yield trials. Hybrids with male parents developed by mass selection did not differ significantly for grain yield and panicles/plant from those with parents chosen on the basis of S₁ yield tests. The S₁-selection hybrids …

Pollen Fertility And Agronomic Performance Of Sorghum Hybrids With Different Male-Sterility-Inducing Cytoplasms, R. E. Secrist, R. E. Atkins

Journal of the Iowa Academy of Science: JIAS

Effects of three sources of male-sterility-inducing cytoplasm in sorghum [Sorghum bicolor (L.) Moench] were compared in crosses with 217 male parents. Hybrids of these parents and A2 Redbine 58', 'A3 Combine Kafir 60', and 'A4 Martin' female parents were evaluated for percentage stained pollen, seed set of bagged panicles, plant height, and days to midbloom. Additionally, hybrids of 12 of the inbreds crossed to each female parent were evaluated for grain yield and other agronomic traits in comparison with hybrids in A1 male-sterility-inducing cytoplasm.

Twenty-one inbreds restored pollen fertility to hybrids with A2 cytoplasm, 11 restored pollen fertility to …

Agronomic Performance Of Sorghum Hybrids Produced By Using Different Male-Sterility-Inducing Cytoplasms, A. J. Maves, R. E. Atkins

Journal of the Iowa Academy of Science: JIAS

Experiments were conducted in three environments in Iowa to obtain information on the effects of different cytoplasms on agronomic characters in grain sorghum (Sorghum bicolor L. Moench) hybrids. Compared with A1 cytoplasm, A2 and A3 cytoplasms delayed flowering; reduced the percentage of fertile pollen, the number of seeds per panicle, and grain yield; and increased 100-seed weight of the hybrids. Hybrids with A2 or A3 cytoplasm did not differ (p ≥0.05) from those in the A1 cytoplasm for plant height, panicles per plant, or for length, width, and area of the third and fourth leaves from the top of …