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Yields of S 1 Lines from Original and Advanced Synthetic Varieties of Maize 1
Author(s) -
Genter C. F.
Publication year - 1971
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1971.0011183x001100060016x
Subject(s) - sss* , inbreeding , inbreeding depression , biology , zea mays , yield (engineering) , population , agronomy , mathematics , demography , physics , mathematical optimization , sociology , thermodynamics
Four maize ( Zea mays L.) synthetic varieties were selfed and approximately 200 S 1 lines of each were grown in separate replicated yield trials with the parental populations to compare inbreeding depressions and yield distributions among the S 1 lines. The four parental populations were (i) ‘iowa Stiff Stalk Synthetic,’ SSS, (ii) an advanced synthetic derived from SSS by seven cycles of recurrent selection based on half‐sib yield, SSS(HT)C7, (iii) ‘Virginia Corn Belt‐Southern Synthetic,’ CBS, and (iv) an advance synthetic derived from CBS by four cycles of recurrent selection for S 1 yield, CBS(S)C4. Inbreeding depression was lower for S 1 lines from each of the advanced synthetics than for those of the corresponding original and was lowest for the S 1 lines from SSS(HT)C7. Inbreeding depressions were 39.1 and 27.8%, respectively, for S 1 lines from SSS and SSS(HT)C7, and 38.3 and 32.5%, respectively, for S 1 lines from CBS and CBS(S)C4. S 1 lines from SSS(HT)C7 averaged 9.3% higher in yield than those from SSS, although the range of yields was less at both extremes for lines from the advanced population. S 1 lines from CBS(S)C4 averaged 27.2% higher than those from CBS with a comparable range of yields. SSS(HT)C7 yielded slightly less than SSS. CBS(S)C4 yielded approximately 19% more than CBS. In all populations the maximum S 1 yield approximated that of the parental source. Two S 1 lines from CBS(S)C4 were comparable in yield to that of a double‐cross hybrid check variety. One effective means of increasing inbred line yields appears to be increasing the yields of parental source populations.