Multivariate analysis based evaluation of maize genotypes under high temperature stress

The pace of world population growth is very rapid, and the main culprit in this phenomenon is urbanization. The demand for food is also expected to increase, especially for crops used as staple foods. To counter these problems, collaboration is needed among different organizations in the world. In response to this situation the Maize and Millets Research Institute, Yusafwala, Sahiwal, Pakistan (MMRI) is working with the International Maize and Wheat Improvement Center (CIMMYT) on different projects to identify and characterize heat-tolerant genotypes. High temperatures affect pollination and seed setting rates, and have reduced maize yields significantly by as much as 80% to 90%. A trial named HSH-II-117 with 70 maize accessions (64 imported from CIMMYT, Mexico and 6 local checks) was carried out at MMRI in spring 2017 under a randomized complete block design with two replications. Data were collected for different morphological traits. Statistically significance differences among genotypes were determined, and principle components analysis and cluster analysis were used. Significant differences among genotypes were found for all traits except ear height. The percentage coefficient of variance (CV%) for all traits was less than 20%, so all traits could be used for further analysis. Genotypes P1543©, ZH1635, FH949©, ZH1639 and ZH16902 can be recommended as short-duration, high-yield genotypes, while YH1898©, ZH16900 and ZH1655 can be recommended as medium-duration, high-yield genotypes. All the recommended genotypes had the lowest stem lodging and root lodging, and the shortest time to the end of anthesis