The Study and Comparison of 3 Foxtail Millet (Setaria italica L.) Cultivars in Different Phenological Stages in Karaj Region

The determination of forage quality is one of the most important factors essential to appropriate field management. The most important factor, effective on forage quality, is the growth stage; by studying on phenological stages of the forage, we can determine the suitable grazing time. Since different cultivars of forage crops have different feed qualities in each of their growth stages, for the purpose of investigation of genetic diversity of forage yields and their quantitative characters, we studied three foxtail millet cultivars, namely KFM1, KFM6 and KFM9 in three phenological stages including vegetative growth stage, flowering stage and seeding stage by use of a factorial experimental design with a complete bock basic design with 3 replications in Karaj, Iran. Except for ADFand crude fiber percentage, the difference between the other feed quality indices as well as wet and dry yields, among the different cultivars and the three growth phases of the cultivars, was not significant (P < 0.01). Further, the interaction effect between different cultivars and also the phenological growth stages was statistically significant only in connection with wet and dry yield. Proportional to the development of growth stages, approximately in all cultivars, the crude protein percentage and digestive dry material percentage are decreased and the fiber content increased. In general, according to the measured indices, KFM1 has had the highest feed quality and, taking into account its appropriate feed quality, was selected as the outstanding cultivar. The vegetative growth stage (1st phenological stage), from the point of view of feed quality indices, was higher than the two other stages (except for water soluble carbohydrates); but, considering relatively small forage energy difference between stages 1st and 2nd phenological stages, and also higher production and readiness of the fields (ranges) for grazing, the 2nd phenological stage (flowering stage) was selected as the best time for grazing (by use of grazing systems).