Evaluation of forage yield and yield stability of 16 forage maize genotypes of local and exotic origin to introduce the farmers

In order to study the adaptability and determine the cultivation value of new corn hybrids, 16 forage maize genotypes of local and exotic origin were evaluated along with three common genotypes (KSC704, Bolson and Massil) in four different regions (Karaj, Maghan, Jovein and Dezful) using randomized complete block design with four replications in two years (2020 and 2021). Important traits such as days to flowering, plant height, ear height, ear-to-plant ratio and wet silage yield were recorded, based on the manual of value for cultivation and use test. To evaluate the yield stability, Francis and Kannenberg's environmental coefficient of variation was used. The results of two-years mean comparison of yield showed that Egean, Sy-Lavaredo, ZP873, Zarin2 and Zarin3 hybrids had the highest forage yield with 65.4, 64.8, 64.7, 63.8 and 62.3 tons per hectare, respectively, While the average yield of check varieties was 60 tons per hectare. Sy-Andromeda, Sy-Lavaredo, Egean, Jeta poly, Zarin 1, Zarin 2, Zarin 3 and ZP873 hybrids can be introduced with general adaptability, due to their higher yield and yield stability in comparison with the check varieties. Sy-Bilbao and BT-6470 hybrids are recommended in Karaj and Jovein regions and Ajeeb and ZP600 hybrids are also recommended in Jovein region with specific adaptability. ZP707, RGT-Joxxlin, RGT-Coruxxo and Exxupery hybrids do not deserve to release as a new variety because of low forage yield and yield adaptability in comparison with the check varieties.