Itthiphon khong pui nitrogen to nitrate reductase phonphalit lae laksana thang kan kaset bang prakan nai khaophot.
1977
Suphot Phuangphuphong | Kitima Manthranon
An experiment was conducted at the National Corn and Sorghum Research Center, Nakornrajsima from August to November in 1976. Split plot design was used with four corn varieties namely: Suwan 1, Pakchong 1602, Suwan DMR source 2 and Thai Comp. no. 1. Early DMR served as main plots and nitrogen levels of 0, 39 and 140 kg N/ha as sub-plots. Leaf samples were collected for nitrate reductase activity (NRA) determination at 46, 55, 63, 71 and 86 days after emergence. NRA of Thai Comp. no. 1 Early DMR and Suwan 1 tended to be higher than Pakchong 1602 and Suwan DMR source 2. A significant difference in NRA, due to rates of nitrogen fertilizer, was detected at all growth stages under investigation. The highest NRA was observed at 46 days after emergence and gradually declined thereafter. Grain yield and grain protein percentage were found to be different among varieties and nitrogen rates. Grain yield and grain protein percentage increased with increasing rates of nitrogen fertilizer. An application of nitrogen fertilizer had no effect on seed size and number of ears but caused an increase in seed number per ear.
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