Line X Tester Analysis for Protein Content in Quality Protein Maize (QPM) (Zea mays L.) Genotypes

Aims: To determine superior cross combination between QPM and tester (normal maize) genotypes in protein, tryptophan and lysine content so to enhanced protein content in locally adopted Maize Varieties (Tester) through Line X Tester method aimed in reducing protein deficiency in the study area and sub-Saharan Africa at large.

Study Design: Randomized Complete Block Design (RCBD) with three replicates and two border rows were used at the end of each replicate to minimize the border effect. Twenty-four 24 (12 x 2) crosses combinations were recovered through the Line X Tester Mating Method.

Place and Duration of Study: Field trial was conducted at Jega Teaching and Research farm of Kebbi State University of Science and Technology, Aliero (KSUSTA), Kebbi State Nigeria, during 2018 and 2019 rainy seasons.

Methodology: Experimental material comprised twelve quality protein maize (QPM) (female parents), two testers (male parents or normal maize) with diverse genetic base and one check for comparison (CML312/CML442 tester A and CML202/CML395 tester B and one check Yar acre C) were grown. The emasculation was carried out where the tassels of the female plants (seed parents or line) were removed immediately as soon as appeared, through the process called detasseling and Ear where put in selfing bag for 1 to 2 days after emergence and tassels of selected male parents (Tester) were covered with waterproof selfing bag one day after emergence, pollens from tester were dusted over the silk of line and care was taken in each stage to avoid contamination of pollen grains from tagged tester with foreign pollens.

Results: Analysis of Variance revealed that, genotypes CML503 (L4 x T1) recorded highest in crude protein in a combined mean performance with 9.1% but recorded lowest lysine and tryptophan of 3.1% and 0.4% respectively and there was drastic reduction in crude protein from 2018 (9.4%) to 2019 (8.8%), lysine from 2018 (4.1%) to 2019 (3.9%) and tryptophan from 2018 (0.8%) to 2019 (0.6%), However, local check recorded an increase in crude protein, lysine and tryptophan Crude protein increased from 2018 (1.4%) to 2019 (2.4%) and in combined mean performance (5.4%), lysine also increased from 2018 (0.2%) to 2019 (0.9%) and tryptophan 2018 (0.002%) to 2019 (0.90%).

Conclusion: Study concluded that highly significant differences among genotypes indicated the presence of inherent genetic differences among treatments and hybrid of the cross between QPM CML503 and the tester-A (L4 x T1) could be used for breeding programme aimed at protein improvement and therefore, could be grown by the maize producers for crude protein, lysine and tryptophan.