稻品種間胴割粒率差異性之探討

Abstract

以引自日本良質米品種豐錦等78個，加上本省推廣栽培品種臺農70號等6個，共計84個為供試品種。在栽培管理與收穫調製力求均一之條件下，探討胴割粒率在水稻品種間之變異情形。初步結果顯示胴割粒率在水稻品種間有極大之差異存在，其變異範圍自2.0%至71.33%，而以介於2.0%到10.0%之間者佔多數，計有30品種，佔供試品種數之35.7%。就各類胴割模式在供試品種內之出現頻率而言，以第一、二級模式出現之比率最高分別為100%與97.6%。而以第四級模式出現的比率最低僅有8.3%。若就同一品種上所出現之胴割模式數而言，則以出現一種及六種等二者為最低分別有2品種佔2.38%，而以出現3種者為最高，有41品種佔48.81%。顯示除胴割粒率在水稻品種間存有明顯之差異外，各類胴割模式之出現頻率及在同一品種上所出現之胴割模式數，因品種別亦有很大之差異。由是推論，欲在水稻品種間實施低胴割粒率之篩選，以降低碎米率來提高完整米率，其成效是可預期的。 Cracked kernel is an important factor affecting the broken rate of milled rice. Therefore, selecting rice variety with lower percentage of cracked kernel for cultivation is an effective measures to improve the marketing value and cooking quality of rice. In the present study, 84 Japonica rice varieties were cultivated under uniform condit-ions and the percentages of cracked kernels were investigated. Significant difference in the occurrence rate of cracked kernel, ranging from 2 to 71.33%, were observed among the tested varieties. Thirty varieties, or 35.7% of total, showed a cracking percentage below 10%. Based on the appearance of the cracked kernels, cracking types could be divided into 6 models (refer to Fig. 1). The cracking type belonging to model 1 could be discovered in all varieties while models 2, 3, 4, 5 and 6 existed in 97.6, 75.0, 8.3, 9.5 and 28.6% of the tested varieties, respectively. Furthermore, most varieties showed a combination of more than one type of cracked kernels. Experimental results suggested that selecting varieties with lower percentage of cracked kernels for rice improvement should be applicable.