Abstract
Accurate estimation of genetic variability present in tropical maize inbreds with varying reactions to Strigahermonthica infestation is essential for efficient and sustainable utilization to ensure increased genetic gain in a breeding program. Thirty-six early maturing maize inbred lines and 156 single cross hybrids were evaluated under Striga-infested and non-infested conditions in Nigeria during the 2014 and 2015 cropping seasons. Under Striga infestation, grain yield ranged from 1134 kg ha−1 for TZEI 26 × TZEI 5 to 5362 kg ha−1 for TZdEI 173 × TZdEI 280. The average yield reduction of the hybrids under Striga infestation was 44% relative to the performance under non-infested environments. Using 4440 high-quality DArT markers, clustering and population structure analyses separated the inbred lines into three distinct groups based on the genetic distance indicating high level of genetic variability among the lines. The base index of the International Institute of Tropical Agriculture (IITA) identified 50% of the inbred lines as Striga resistant. The genetic diversity study provided an opportunity for selecting divergent parents for tagging candidate genes and quantitative trait loci for marker-assisted introgression of Striga resistance genes into early maturing tropical maize breeding populations. The most reliable secondary trait for indirect selection for grain yield under Striga infestation was the ear aspect.
Highlights
The introgression of novel genes for Striga resistance from the wild relative of maize, Zea diploperennis L., into the background of cultivated maize is a resourceful approach for genetic and Agronomy 2020, 10, 1478; doi:10.3390/agronomy10101478 www.mdpi.com/journal/agronomyAgronomy 2020, 10, 1478 physiological studies [1,2,3]
Significant (p < 0.01) sets and environment–sets interaction effects were obtained for most measured traits except sets mean squares for Striga damage at eight weeks after planting (WAP); environments–sets interactions mean squares for anthesis-silking interval (ASI) and Ears per plant (EPP)
Interactions of the general combining ability (GCA)-male and GCA-female with the environment were highly significant for grain yield and other agronomic traits, except E–GCA-male for Striga damage at eight WAP
Summary
The introgression of novel genes for Striga resistance from the wild relative of maize, Zea diploperennis L., into the background of cultivated maize is a resourceful approach for genetic and Agronomy 2020, 10, 1478; doi:10.3390/agronomy10101478 www.mdpi.com/journal/agronomyAgronomy 2020, 10, 1478 physiological studies [1,2,3]. A thorough understanding of the genetic diversity in the maize inbred lines and assessment of their reactions to Striga are essential for systematic exploitation, to provide the capacity to meet changing environments and market requirements [4]. Genetic diversity in maize has been assessed using several types of DNA markers including restriction fragment length polymorphism (RFLP), randomly amplified polymorphism DNA (RAPD), simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. These markers have provided effective genotyping and are not affected by the different processes of plant physiology or the environment [8,9,10,11].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
