Evaluation of Single Cross Yellow Maize Hybrids for Agronomic and Carotenoid Traits

Abstract

Provitamin A bioforitification of maize endosperm was found to be most convenient solution to the resolve its deficiency in the masses. Continuous efforts for persistent evaluation of diverse genetic material are prerequisite for genetic improvement of maize endosperm for provitamin A. Distinctively selected inbred lines and testers were evaluated for their yield and provitamin A related performance in single cross F1 hybrid combinations. Total 50 single cross hybrids were evaluated for different agronomic and carotenoid related traits. Significant differences were observed among genotypes, lines, testers and line × tester interaction for studied traits. L5, L6 and T1 had high GCA effects for YPH, RPC and FW whereas, L1, L5 and T4 had high GCA effects for TCC, PVAC and NPVAC. Among studied crosses, L7×T3, L8×T4 and L5×T2 had high SCA effects for PVAC whereas, L2×T5, L3×T3 and L4×T2 had high SCA effects for YPH. L3×T3 had high SCA effects for YPH, TCC, PVAC and NPVAC. L8×T4 had high SCA effects for PVAC, RPC and FW. L2×T5 had high SCA effects for PVAC, YPH, NPVAC and TCC. Most of variability was contributed by L×T interaction which showed that performance of the parents could only be evaluated in specific cross combinations. Phenotypic variances and phenotypic coefficient of variations were higher which showed that performance of the crosses was also dependent on the environmental factors. Gene action showed that all of the traits were under the control of non-additive gene action which strongly directs the manipulation of heterosis breeding for genetic improvement of studied traits. L3×T3, L5×T4, L3×T1, L4×T3, L2×T1, L8×T3 and L5×T2 for RPC and TCC whereas, L1×T1, L3×T5, L7×T1, L10×T5, L7×T2 and L9×T1 for FW, YPH and PVAC had highest better parent heterosis. Results of Kempthorne's analysis and GGE biplot analysis were comparable for estimation of GCA, SCA effects and identification of desired crosses. Therefore, GGE biplot could be preferred for providing visual explanation of the effects and additionally provides information about heterotic grouping of testers, SCA effects of parents, best parent and best crosses. Combining ability, gene action and heterosis studies based on Kempthorne's analysis and GGE biplot analysis revealed that genetic improvement can be made for studied agronomic and carotenoid related traits. Improvement of yield and provitamin A carotenoids may help the peoples of Pakistan to suffice the food security issue and to alleviate the sub-clinical symptoms of vitamin A deficiency.

Introductory Chapter: Transgenics—Crops Tailored for Novel Traits

“…Provitamin A deficiency that results in night blindness in masses may be addressed through genetic improvement of crops like maize. In a study where single-cross maize yellow hybrids were evaluated for carotenoid contents [3] since biofortification of maize, endosperm is found to be the most convenient solution addressing its deficiency. Hence, improved contents of provitamin A carotenoids in maize may help Pakistani populace to alleviate the subclinical symptoms of vitamin A deficiency [4].…”

“…Iron-fortified products are the prime examples of it. Pyramiding genes that encode provitamin A, transgenically or naturally, in crops like rice [1], potatoes [2], and maize [3,4] have made these crops a rich source of provitamin A. In addition to adding nutritional elements in crops, the transgenic technology has led the scientists to tailor medicinal traits, for example, therapeutic [5,6] and antigen proteins [7].…”

Breeding for provitamin A biofortification of maize (Zea mays L.)

“…Both types of gene actions were prevalent depending upon the genetic background of subjected germplasm which determines further breeding methods. Maqbool, Aslam, Khan, Beshir and Ahsan () evaluated the 50 F 1 single‐cross yellow maize hybrids developed from Pakistan‐originated parental lines. They analysed the combining abilities, gene action and heterosis.…”