BREEDING SORGHUM FOR SEEDLING COLD SURVIVAL AND DEVELOPMENT
Abstract
A genetically broad-based random-mating grain sorghum population, Purdue Population 9 (PP9), was used as a source population in selecting for increased seedling cold tolerance. This selected population, Purdue Population 9 Cold Tolerant (PP9CT), was developed through a phenotypic recurrent selection procedure utilizing natural selection in early spring plantings. The progress made by the selection procedure was evaluated in early spring plantings in 1981 and 1982. In 1981, C(,0)-C(,3) and 2 checks were evaluated in plots of 100 seeds using a randomized complete block design. In 1982 the C(,4) generation was also included. The results from the first year indicated that a 10.6% increase in cold emergence had been accomplished after 3 cycles of selection. Data from 1982 indicated a 15.0% increase in cold emergence after 4 cycles of selection. Regression analysis on the combined tests showed a linear response with a rate increase of 2.77%/cycle. The traits of plant height, days to half bloom, seed color, and grain yield were evaluated to determine the correlated responses in PP9CT following selection for seedling cold tolerance. These traits were evaluated in separate plantings from the emergence trials in 1981 and 1982 using a randomized complete block design. Plant height showed a somewhat erratic response. Days to half bloom decreased by 0.55 days/cycle, seed color increased by 0.13 color units/cycle, and grain yield increased by 197.74 kg/ha/cycle. Sorghum introductions from China, kaoliangs, were evaluated as a possible source of cold tolerant genes. Results indicated that some of these lines had very good potential as sources of sorghum cold tolerant genes.
Degree
Ph.D.
Subject Area
Agronomy
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