Knowledge Center Catalog

Grey leaf spot disease of maize-loss assessment, genetic studies and breeding for resistance in Zambia

By: Contributor(s): Material type: TextTextPublication details: Nairobi (Kenya) KARI|CIMMYT : 2002Description: p. 60-65ISBN:
  • 970-648-120-6
Subject(s): DDC classification:
  • 338.16 FRI
Summary: With the introduction and spread of a previously unreported disease, Grey Leaf Spot (GLS) of maize in the country in the mid 1990s, all old bybrids succumbed to the disease. These bybrids were developed by Government research supported by various donors and availed to Zambia Seed Company Ltd. (Zamseed) who had exclusive rights to produce and market government-bred material. Phasing out of donor support at this critical stage created a vacuum in maize breeding. To fill the gap, the company was forced to start a research department to take control of its research Deeds. In response to the GLS problem, the research department adopted a dual pronged approach to firstly improve genetic resistance of old bybrids as a short-term measure and, secondly, initiated a long-term resistance breeding programme. Replacement of susceptible parents by resistant versions in old hybrids brought remarkable improvement in most hybrids. Yield losses due to GLS ranged from 28 to 54% with an average loss of 33.5%. In diallel studies both GCA and SCA variances were found highly significant for GLS indicating the importance of both additive and non-additive components although GCA was relatively more important. GCA effects of parents were good indicators of hybrid performance in general but failed to explain performance of all bybrids. Screening of germplasm revealed abundance of resistance in local material and prospects of breeding for resistance appear good.
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With the introduction and spread of a previously unreported disease, Grey Leaf Spot (GLS) of maize in the country in the mid 1990s, all old bybrids succumbed to the disease. These bybrids were developed by Government research supported by various donors and availed to Zambia Seed Company Ltd. (Zamseed) who had exclusive rights to produce and market government-bred material. Phasing out of donor support at this critical stage created a vacuum in maize breeding. To fill the gap, the company was forced to start a research department to take control of its research Deeds. In response to the GLS problem, the research department adopted a dual pronged approach to firstly improve genetic resistance of old bybrids as a short-term measure and, secondly, initiated a long-term resistance breeding programme. Replacement of susceptible parents by resistant versions in old hybrids brought remarkable improvement in most hybrids. Yield losses due to GLS ranged from 28 to 54% with an average loss of 33.5%. In diallel studies both GCA and SCA variances were found highly significant for GLS indicating the importance of both additive and non-additive components although GCA was relatively more important. GCA effects of parents were good indicators of hybrid performance in general but failed to explain performance of all bybrids. Screening of germplasm revealed abundance of resistance in local material and prospects of breeding for resistance appear good.

English

0409|AGRIS 0401|AL-Maize Program

Juan Carlos Mendieta

CIMMYT Publications Collection


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