[1] IRRI, Soc Sci Div, Los Banos, Philippines
[2] Int Res Ctr Agr Sci JIRCAS, Tsukuba, Ibaraki 3058686, Japan
[3] Zhongshan Univ Econ & Law, Wuhan 430073, Hubei Province, Peoples R China
[4] Khon Kaen Univ, Khon Kaen 40002, Thailand
[5] Ranchi Univ, Dept Econ, Ranchi, Bihar, India
[6] Orissa Univ Agr & Technol, Bhubaneswar 751003, Orissa, India
[7] Indira Gandhi Agr Univ, Raipur, Madhya Pradesh, India