选育和推广良种是投资少、收益大、见效快的重要增产措施。根据广东省农科院情报所袁志清等计算,我省水稻良种选育的投资与效益之比约为1比100,即每投资1元可收到社会效益100元。我省水稻良种选育、推广工作有较好的基础,社会效益显著。建国后已进行三四次较大的良种更换,在农业生产条件的不断改善配合下,每次更换新良种,都促进稻谷单产提高30—40公斤。从选育、推广良种(组合)角度考虑,在进一步提高良种产量,增强对病虫灾害的抗性 Breeding and promotion of improved varieties is an important measure to increase production with less investment, greater returns and quick results. According to Yuan Zhiqing, an institute of information science of Guangdong Academy of Agricultural Sciences, the investment and benefit ratio of rice breeding in our province is about 1 to 100, that is, the social benefit of 100 yuan can be received for every 1 yuan of investment. Rice breeding in our province, promotion work has a better foundation, social benefits significantly. After the founding of the People’s Republic of China, three or four major thoroughbred species replacements have taken place. Under the continuous improvement and cooperation of agricultural production conditions, each time a new breed of new breeds is changed, paddy yields have been boosted by 30-40 kg. From the perspective of breeding and popularizing improved varieties (combinations), we will further increase the yield of improved varieties and increase their resistance to pests and diseases