The Ratooning Potential of Several Early-Ripening Rice Cultivar in Korea

Abstract

Rice ratooning is the production of a second rice crop from the stubble left behind after the main-crop harvest. The main advantage of rice ratooning is that in areas where rice is the main crop, double crop of rice can be grown for additional returns. Eight cultivars of rice were tested for estimation their ratooning ability. The main crop was harvested at mass maturity, after which the tillers were mowed to stubbles of about 10 cm tall. And then left without any further input, until the ratooned plant were ready for harvest. Highly significant variations were detected in the ratoon performance among cultivars, with ratoon ability ranging from 0% ('Unkwang', 'Jopeyong', 'Odae', 'Nokyang') to 33% ('Jinbuol') in their grain yield. The maximum grain yield from ratoon rice was 202 and 203 kg/10a for 'Jinbuol' and 'Joun' followed by 'Junamjoseng' 174kg/10a. Protein and amylose contents of ratoon rice were more increased than those of main rice. The platability value of cooked rice of ratoon was lower than that of main crop. Germination rate of the previous year's harvest of rice was not significantly different between ratoon and main crop. This rice ratooning system requires short duration, creating possibility for growing another crop in the same cropping year and offers an opportunity to increase cropping intensity per unit of cultivated areas.

Evaluation and Comparative Analysis of Meteorological Data, Moisture Content, and Rice Panicle Threshability

“…Although we detected a high correlation in some varieties ('M 488' and 'M 225') for temperature parameters (T max and T mean ), the minimum temperature was the only factor that correlated significantly to the TF in the average of all varieties. This result confirms the consequence of Shin et al who reported a higher significant impact (0.759 *) on TF [14]. On the other hand, the grain threshability depends on the shape of the separation pilei [20], the strength of spikelet attachment to the panicle [30], and the different moisture contents of the seed [31].…”

“…More research groups reported that the grain threshing habit of rice is related to three factors: the form of the abscission layer (AL) at the base of sterile lemmas [12,13], environmental factors such as humidity and temperature [8,14], and the genetic constitution of the variety [15][16][17]. Although the formation of the AL is determined by genes [12,18], a classification based on the AL is very difficult [19].…”