Screening maize (Zea mays L.) genotypes for phosphorus deficiency at the seedling stage

Authors: MD. GOLAM AZAM, UMAKANTA SARKER, MD. SHALIM UDDIN

Abstract: A study was conducted at Bangladesh Agricultural Research Institute's greenhouse with 48 maize genotypes through hydroponic culture. Two levels of treatment, namely, low phosphorus (LP) (2.5 × 10^-6 mol L^-1 of KH₂PO₄) and normal phosphorus (NP) (2.5 × 10^-4 mol L^-1 of KH₂PO₄), were used for this study. Morphologically, plants behave differently in low phosphorus conditions than in normal phosphorus environments. Large augmented roots were found in the plant in low phosphorus conditions. The results revealed that chlorophyll contents, shoot length, root length shoot dry weight, root dry weight, leaf area, and root/shoot ratio might be considered critical traits for screening low phosphorus tolerant maize at the seedling stage. The first four principal components (PCs) described 89% of the total variation. Forty-eight maize genotypes formed four main groups or clusters. Among these four cluster groups, except for the SPAD value, the highest number of the mean values for root length, shoot length, root/shoot ratio, root volume, leaf area, root dry weight, shoot dry weight, and total dry weight were obtained from cluster group three. By constructing a genotype × trait biplot with nine traits recorded in 48 genotypes, the highest positive relationship was recorded in total dry weight (TDW) with root dry weight (RDW), shoot dry weight (SDW), and root volume (RV). The results revealed that the SPAD value was weakly correlated with other traits. In the current study, the studied characters were highly heritable. Based on the performance, G10, G18, G23, G27, G29, G33, and G34 could be considered low phosphorus tolerant genotypes. The results of combining abilities revealed that the genotypes G9, G13, G29, G31, and G39 could be used as parents in breeding activities. The present study offers guidelines for plant breeders to develop low phosphorus tolerant maize cultivars for the sustainability of maize production in the modern era of the changing climate.

Keywords: Maize, combining ability, heritability, hydroponics, phosphorus deficiency

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