Among the tropical tuber crops, cassava (Manihot esculenta Crantz) deserves special attention as regards to its higher biological efficiency in terms of dry matter production which incidentally implies to the higher amount of nutrient extraction from the soil resulting in better response to the application of manures and fertilizers. Among the major nutrients, Potassium (K) is considered as the key nutrient for cassava owing to its influence both in tuber yield and tuber quality. The above facts as well as the availability of sufficient cassava genotypes in the germplasm collection of ICAR-CTCRI made us to initiate research work to screen cassava germplasm including the pre breeding lines. The objective being to identify K efficient genotypes which can yield well under limited availability of K so that the external application of K can be reduced. This paper describes the wide variation noticed during the pre evaluation of 83 elite genotypes which was done as a prelude in the screening and identification of K efficient genotypes. The characters studied were tuber yield, tuber characters, plant dry matter percentage, plant K content, tuber quality (starch, cyanogenic glucosides) attributes, physiological efficiency and plant biometric characters. The variation among the genotypes for the above traits was assessed by making some yardstick for classification which in turn helped in determining the percent distribution of genotypes in each category. The variation among the genotypes were further affirmed through principal component analysis, wherein the first five components explained more than 77% of variability and the cluster analysis performed grouped these genotypes into five clusters. The biplot showed the traits which are closely linked to the genotypes. The dendrogram constructed indicated similar genotypes to that of the clusters to the extent of more than 50% revealing the association of members with similar traits in clusters and dendrograms. The study helped in establishing the drastic variation among the genotypes along with identification of six genotypes viz., Aniyoor, 7 Sahya (2), 7 III E3-5, W-19, CR 43-8, 6-6 for further detailed experimentation to identify K efficient genotypes.

中文翻译：

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通过不同的统计工具对木薯（Manihot esculenta Crantz）种质进行基因型变异的预评估，以鉴定 K 有效基因型。

在热带块茎作物中，木薯（Manihot esculenta Crantz）值得特别关注，因为它在干物质生产方面具有较高的生物效率，这顺便意味着从土壤中提取的养分含量更高，从而对肥料施用有更好的反应和肥料。在主要营养素中，钾（K）因其对块茎产量和块茎品质的影响而被认为是木薯的关键营养素。上述事实以及 ICAR-CTCRI 种质资源库中充足的木薯基因型的可用性促使我们启动了筛选木薯种质（包括预育种系）的研究工作。目的是鉴定钾高效基因型，在钾的利用率有限的情况下能够获得良好的产量，从而减少钾的外部应用。本文描述了在对 83 个优良基因型进行预评估时注意到的广泛变异，这是筛选和鉴定 K 高效基因型的前奏。研究的性状包括块茎产量、块茎性状、植物干物质百分比、植物钾含量、块茎品质（淀粉、氰苷）属性、生理效率和植物生物特征。通过制定一些分类标准来评估上述性状的基因型之间的变异，这反过来又有助于确定每个类别中基因型的百分比分布。通过主成分分析进一步证实了基因型之间的变异，其中前五个成分解释了超过 77% 的变异性，并且进行的聚类分析将这些基因型分为五个聚类。双标图显示了与基因型密切相关的性状。构建的树状图显示与簇相似的基因型超过 50%，揭示了簇和树状图中具有相似性状的成员之间的关联。该研究帮助确定了基因型之间的巨大变异，并鉴定了六种基因型，即 Aniyoor、7 Sahya (2)、7 III E3-5、W-19、CR 43-8、6-6，以进行进一步详细的实验识别 K 有效基因型。