Chemical composition, milling and cooking quality of mechanically transplanted rice in relation to seedling age and plant population

New ways of rice growing like direct seeding, bed planting and mechanical transplanting are being advocated to reduce fuel and labour costs and increase profitability. Little information is available on how these practices affect grain quality of rice, the latter one in particular. Different parameters associated with grain quality (nitrogen, protein, amylose, amylopectin content, milling and cooking quality) of rice transplanted mechanically with Japanese transplanter by using seedlings (rice cv. PR-115) of different age (3, 4 and 5 weeks old) and at different plant population levels (21, 24 and 28 plants m−2) were studied. The nitrogen content in grains decreased significantly with increasing age of seedlings and decreasing plant population levels, which led to the corresponding decline in the protein content in the grains. Similar trend was noticed for amylose content; however, it was opposite in case of amylopectin. Non-significant differences in milling quality (brown rice, white rice, head rice and broken grains) were observed in seedlings of different age and plant population levels tested. Cooking time showed positive correlation with protein content (At p d” 5, r = 0.97 and 0.99 for age of seedlings in 2010 and 2011, respectively and 0.99 for plant population levels in both the years). The length: breadth ratio of cooked rice and cooking co-efficient increased with seedling age and plant population levels.