Document Type : Research Paper
Authors
1
PhD student, Department of Plant Production & Genetics, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.
2
Associate Professor, Department of Plant Production & Genetics, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
10.22124/cr.2024.26326.1802
Abstract
Introduction
The low diversity and genetic basis of germplasm in temperate regions is a significant challenge in maize breeding. The genetic characterization of maize germplasm has revealed that tropical and subtropical germplasm often contain a broader genetic base and show larger diversity than that in temperate populations. The use of foreign germplasm, especially from tropical and subtropical regions, has been identified as a potential solution to strengthen the genetic base of germplasm in temperate regions. However, the efficiency of screening methods for superior and suitable sources of exotic germplasm remains a major challenge. The study aimed to determine the optimum number of testers and suitable testers for screening maize lines derived from tropical and subtropical CIMMYT germplasm.
Materials and methods
The research involved crossing three temperate maize testers (MO17, B73, K1264/5-1) with 25 lines originated from the CIMMYT maize germplasm based on the line × tester mating system. A total of 75 crosses, along with the control hybrid (SC704), were evaluated in the experimental design of Alpha Lattice in two replications with four incomplete blocks in each replication in two regions (Moghan and Jiroft). The results showed that out of the 75 crosses, 32 crosses had higher and significant grain yield compared to the SC704 (control variety). The GGE biplot procedure and methodology proposed by Fan et al. (2010), were used to analyze the data obtained from the study.
Research findings
The range of the superiority of the superior cross compared to the control hybrid was between 1.46 and 3.77 tons per hectare. These findings highlight the potential of utilizing tropical and subtropical germplasm to enhance maize yield in temperate regions. Additionally, the study identified lines No. 22, 9, 19, 12, 20, 5, 17, 21, 24, 14, 15, 23, and 11 respectively had the highest positive general combining ability (GCA) for grain yield. In general, in terms of grain yield, GCA, and specific combining ability (SCA), it is possible to directly use lines No. 4, 5, 9, 11, 12, 19, 22, and 24 extracted from tropical and subtropical CIMMYT germplasm to improve grain yield in temperate regions. The performance of the temperate maize testers showed that testers B73 and MO17 were highly efficient in selecting superior line derived from tropical and subtropical CIMMYT germplasm.The results show that one inbred tester effectively selected most, if not all of the best exotic lines, and that two testers gave more reliable than one tester did.
Conclusion
In general, it could be concluded that it is possible to use maize germplasms from tropical and subtropical regions of CYMMIT to improve grain yield in temperate regions. Also, one temperate maize tester has the ability to distinguish superior sources (not all of them), although the use of two testers greatly reduces the risk of not choosing a superior source.
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