Screening of shade tolerant hybrid maize based on stress tolerance index

Abstract

The development of adaptive and high-yielding maize varieties tolerant to shade stress is the right strategy to increase productivity and national maize production by utilizing the land in shaded conditions or under annual stands with 40% shade intensity. This study aimed to assess the best genetic material before releasing new shade tolerant maize varieties. This experiment was conducted in shaded and unshaded conditions in the Indonesian Cereal Research Institute, Maros, from July-October 2018 in KP. Pandu, North Sulawesi under coconut trees from March-August 2019. The design is using a randomized block design with three replications. The genetic material used consisted of 10 three-lane cross-hybrid maize, SHD01, SHD02, SHD03, SHD04, SHD05, SHD06, SHD07, SHD08, SHD09, and SHD10, and two comparison varieties of three-lane cross-hybrid maize, Bima-19, and P-35. Shade causes a reduction in light intensity, impacting changes in the microclimate under the shade. This is indicated by the dynamics of changes in light intensity which are quite high between maize crops in shaded and unshaded conditions. Tolerance to shade stress was assessed by measuring the difference in yield between unshaded environmental conditions and shaded environmental conditions to assess average productivity under normal and shaded conditions using the stress tolerance index (STI). The adaptive level in shade conditions of the candidate varieties SHD02 and SHD10 was significantly better than that of the Bima 19 and P 35 varieties, with the STI values of these candidates being 0.87 and 0.80, while the two comparison varieties Bima 19 and P 35, were respectively only 0.62.