Innovative Seed Consortium Strengthening the Postrainy Sorghum Seed Systems in India

Sorghum (Sorghum bicolor [L.] Moench) is grown both in rainy (Kharif) and postrainy (Rabi) seasons in India for multiple uses. Of the total sorghum area of 6.5 m ha, postrainy sorghum is grown on ~ 4 m ha area in the black soils under receding soil moisture, after the cessation of rains. The majority of postrainy sorghum production is concentrated across the states of Maharashtra, Karnataka and Andhra Pradesh (Trivedi, 2008; Rana et al., 1999; Hosmani and Chittapur, 1997). Postrainy sorghum growing areas are characterized by low rain fall, low temperatures at flowering time and terminal drought and most of the times sorghum is the only crop option for meeting the food and fodder needs of communities in these areas (Murty et al., 2007; Pray and Nagarajan, 2009; Belum Reddy et. al., 2012; Kholova et al., 2013). Because of these constraints the productivity of postrainy sorghum is low (grain yield ~0.7 t ha‐1). However the grain and stover quality obtained from postrainy sorghum is preferred by the farmers and markets, therefore of higher value. Across postrainy sorghum ecologies, the landrace cultivars possessing white bold lustrous grains, with photoperiod sensitivity, cold tolerance, shoot fly resistance and terminal drought tolerance, like M 35‐1, Dagadi are popular with farmers. There are some improved varieties developed by Indian national program but they are not available to most farmers. The seed replacement ratio is very low (20%) (Fig 1). Further, the market opportunities for grain and fodder are limited restricting it to a subsistence production system. This paper deals with the current status of postrainy sorghum seed systems and innovative approaches to improve the quality seed availability to farmers

Predicting the tensile strength, impact toughness, and hardness of friction stir-welded AA6061-T6 using response surface methodology

In this research, an attempt has been made to develop mathematical models for predicting mechanical properties including ultimate tensile strength, impact toughness, and hardness of the friction stir-welded AA6061-T6 joints at 95 % confidence level. Response surface methodology with central composite design having four parameters and five levels has been used. The four parameters considered were tool pin profile, rotational speed, welding speed, and tool tilt angle. Three confirmation tests were performed to validate the empirical relations. In addition, the influence of the process parameters on ultimate tensile strength, impact toughness, and hardness were investigated. The results indicated that tool pin profile is the most significant parameter in terms of mechanical properties; tool with simple cylindrical pin profile produced weld with high ultimate tensile strength, impact toughness, and hardness. In addition to tool pin profile, rotational speed was more significant compared to welding speed for ultimate tensile strength and impact toughness, whereas welding speed showed dominancy over rotational speed in case of hardness. Optimum conditions of process parameters have been found at which tensile strength of 92 %, impact toughness of 87 %, and hardness of 95 % was achieved in comparison to the base metal. This research will contribute to expand the scientific foundation of friction stir welding of aluminum alloys with emphasis on AA6061-T6. The results will aid the practitioners to develop a clear understanding of the influence of process parameters on mechanical properties and will allow the selection of best combinations of parameters to achieve desired mechanical properties