The Performance of Temperate Maize Testers for SCREENİNg of Tropical and Subtropical Germplasm

Maize germplasm from CIMMYT is genetically most diverse in the world and is exceedingly useful for broadening the genetic base of temperate maize germplasm. It is a tough challenge for improving efficiency and reliability of extracting the best suitable material from exotic germplasm. So, this study was done to determine the optimum number of testers and suitable testers for screening a maize line derived from tropical and subtropical CIMMYT germplasm. For this purpose, four temperate maize testers (MO17, K18, K166B and A679) with thirteen lines originated from CIMMYT germplasm were crossed. Resulted fifty five crosses along with two hybrid checks were evaluated using a randomized complete block design with three replications at Moghan. The results indicate that there was the possibility of direct use of lines No 3, 5 and 7 derived from tropical and subtropical CIMMYT germplasm to improve grain yield. The performance of the temperate maize tester showed that tester K166B had high efficiency in selecting superior line derived from tropical and subtropical CIMMYT germplasm and testers MO17 and A679 were relatively good. Results revealed that one inbred line tester would effectively select most, if not all, of the top best exotic lines and two testers gave more reliable results than one tester did.