ABSTRACT

Bambara groundnut is a highly nutritious underutilized legume with enormous potential to sustain food security in resource-poor countries. However, its potential for improvement through conventional breeding (< 2% success rate) limitation due to the nature of the flowers. Thus, the most viable method of improving this crop is by creating genetic variability through induced mutagenesis. The present study was conducted to evaluate the radiosensitivity of two Bambara groundnut varieties irradiated with acute and chronic gamma irradiations to determine the lethal dose (LD) and growth reduction dose (GR). Healthy seeds of both varieties were exposed to acute gamma irradiation using Cesium-137 at 0, 25, 50, 75, 100, 125, 150, 175, 200, 250, and 300 Gy. For chronic irradiation, two-week-old seedlings of the two genotypes were exposed to accumulated doses of 0, 8.52, 17.04, 35.56, 34.09, 42.61, 59.65, 93.74, 144.87, 255.64, and 570.94 Gy, respectively, in Gamma Green House (GGH) for 60 days. The result from the variance analysis indicated highly significant differences (P < 0.01) for all evaluated traits except for internode length. A linear regression model was developed to determine the mean LD and GR of both genotypes. The established lethal doses (LD_{25, 50, 75}) for acute gamma irradiation on Ex-Sokoto variety were 75, 160, and 250 Gy while 68, 148, and 227 Gy were recorded for Karo variety, respectively. For chronic irradiation, the established growth reduction doses for Ex-Sokoto were 47, 250, and 444 Gy, whereas 70, 264, and 452 Gy were observed in Karo. Variations were observed between the gamma-irradiated genotypes and the methods of irradiations. Generally, the growth, development, and survival rate of Bambara groundnut increase with a decrease in gamma-irradiation doses. The established LD and GR doses from this study can be utilized in large-scale mutagenesis breeding programs for generating a wide range of mutants in Bambara groundnut.

摘要

班巴拉花生是一种营养丰富的未充分利用的豆类，具有在资源贫乏国家维持粮食安全的巨大潜力。然而，由于花朵的性质，其通过常规育种改良的潜力（成功率<2％）受到限制。因此，改良该作物的最可行方法是通过诱变产生遗传变异。进行本研究以评估用急性和慢性伽马射线辐照的两个班巴拉花生品种的放射敏感性，以确定致死剂量（LD）和生长减少剂量（GR）。使用铯137在0、25、50、75、100、125、150、175、200、250和300 Gy下，将这两个品种的健康种子暴露于急性伽玛射线照射。对于慢性辐射，在Gamma温室（GGH）中分别将两种基因型的两周龄幼苗暴露于累积剂量分别为0、8.52、17.04、35.56、34.09、42.61、59.65、93.74、144.87、255.64和570.94 Gy 60天 方差分析的结果表明差异很大（对于所有评估的性状，除节间长度外，P <0.01）。建立了线性回归模型以确定两种基因型的平均LD和GR。确定的致死剂量（LD _25、50、75）对Ex-Sokoto品种的急性伽玛射线照射分别为75、160和250 Gy，而对Karo品种分别记录为68、148和227 Gy。对于慢性照射，Ex-Sokoto的既定生长减少剂量为47、250和444 Gy，而在Karo中观察到为70、264和452 Gy。观察到伽玛射线照射的基因型和照射方法之间存在差异。通常，Bammara花生的生长，发育和存活率会随着伽马辐照剂量的减少而增加。这项研究确定的LD和GR剂量可用于大规模诱变育种计划中，以在Bambara花生中产生各种突变体。