Progress of rice varietal improvement in the dry and intermediate zones of Sri Lanka [breeding]

agronomic characters asia asie breeding breeding methods clima climat climate climatic zones condiciones ambientales condition de milieu cultivar cultivars environment environmental conditions environnement glumiflorae gramineae medio ambiente methode methods monocotyledons oryza oryza sativa pest resistance productividad productivity profitability rendement rendimiento rentabilidad resistance to injurious factors resistencia a las plagas selection site factors sri lanka yields zone climatique