Aina O O, Dixon A G O, Akinrinde E A
Department of Agronomy, University of Ibadan, Ibadan, Nigeria.
Pak J Biol Sci. 2007 Sep 15;10(18):3085-90. doi: 10.3923/pjbs.2007.3085.3090.
Nine cassava genotypes were evaluated for their growth responses and adaptability to soil moisture stress on the field and in the screenhouse in Nigeria. Genotypes were evaluated in three savanna agroecologies in a randomized complete block design with three replicates. Screenhouse evaluation was conducted using three moisture regimes of 75, 50 and 25% Field Capacity (FC) in a two-factor factorial experiment in CRD with three replicates. Morphological and yield data were collected on the field and in the screenhouse. Results showed significant (p < 0.05) difference among genotypes on the field and in the screenhouse. Field moisture stress led to a decline in plant height by 47%, stem girth by 15%, number of tubers by 95% and tuber yield by 87%. Screenhouse moisture condition of 25% FC led to a reduction in plant height by 12.6 and 21.2%, stem girth by 16.3 and 21.7%, number of roots by 94.5 and 88.7% and root weight by 93.3 and 94.9%, respectively at 16 and 30 WAP. Moisture stress therefore resulted into considerable reduction in both vegetative growth and yield of cassava genotypes. Therefore, a concerted effort in breeding cassava for drought tolerance is needed as cassava cultivation is expanding into nontraditional semiarid regions of sub-Saharan Africa. Germplasm introduced from Latin America (especially north-eastern Brazil) is providing a unique source of variability to further broaden the genetic base for drought tolerance in cassava.
在尼日利亚的田间和温室中，对9种木薯基因型进行了生长反应及其对土壤水分胁迫适应性的评估。基因型在三种稀树草原农业生态区采用随机完全区组设计进行评估，重复三次。温室评估在完全随机设计的两因素试验中采用75%、50%和25%田间持水量（FC）这三种水分处理，重复三次。在田间和温室中收集形态学和产量数据。结果表明，田间和温室中的基因型间存在显著（p < 0.05）差异。田间水分胁迫导致株高下降47%，茎围下降15%，块根数量下降95%，块根产量下降87%。温室中25%FC的水分条件导致在16周和30周龄时，株高分别降低12.6%和21.2%，茎围分别降低16.3%和21.7%，根数分别减少94.5%和88.7%，根重分别减少93.3%和94.9%。因此，水分胁迫导致木薯基因型的营养生长和产量大幅降低。所以，鉴于木薯种植正在向撒哈拉以南非洲的非传统半干旱地区扩展，需要齐心协力培育耐旱木薯品种。从拉丁美洲（特别是巴西东北部）引进的种质为进一步拓宽木薯耐旱性的遗传基础提供了独特的变异来源。
