Generation Means Analysis for Estimation of Genetic Parameters for Striga hermonthica Resistance in Maize (Zea mays L.)

Abstract

Striga hermonthica is a parasitic weed species that causes considerable yield loss in susceptible maize cultivars in western Kenya. A generation means analysis was conducted to estimate gene effects influencing resistance/tolerance to Striga hermonthica in maize cultivars adapted to western Kenya. A resistant inbred line developed by Maseno University, MSMP1/P2 was crossed to Striga susceptible inbred line 5057. Experimental units comprised of resistant parent P 1 , susceptible parent P 2 , their F 1 and F 2 generations, and BC 1 P 1 and BC 1 P 2 generations. The six generations were evaluated under Striga sick plots at Nyahera during the short rains of 2012 and long rains of 2013. Field evaluation for entries were grown in a randomized complete block design with three replicates. The results showed significant differences among generations for emerged Striga, Striga damage rating and maize growth including Plant and Ear height. Most of the additive, dominance, additive x additive, additive x dominance and dominance x dominance effects were significant indicating the importance of the additive, dominance and epistatic modes of gene actions in controlling emerged Striga, Striga damage rating, plant and ear height. Most components conferring Striga tolerance behaved in a qualitative manner. Dominance effects had higher mean values over additive effects. Significant dominant genetic effects (d) for Striga emergence and Striga damage rating suggested preponderance of non-additive genetic effects in the inheritance of Striga tolerance. The results also reveal the involvement of duplicate epistasis where the dominance estimate and dominance x dominance interaction had opposite signs. The presence of duplicate type of gene interaction confirms the importance of dominance gene effects.

Inheritance of Striga hermonthica adaptive traits in an early‐maturing white maize inbred line containing resistance genes from Zea diploperennis

“…The resistant parent had lower means for number of emerged Striga plants and Striga damage than the susceptible parent indicating that Striga resistance was expressed by low value for Striga damage and fewer number of emerged Striga plants. Similar results have been reported in Zea mays (Kim, Akintunde, & Walker, ; Mbogo, Dida, & Owuor, ) and Sorghum bicolor (Arnaud, Veronesi, & Thalouarn, ). The BC 1 P 1 means for number of emerged Striga plants at 56 and 70 DAP and Striga damage at 70 DAP skewed towards the resistant parent P 1 .…”

Identification of QTLs Controlling Resistance/Tolerance to Striga hermonthica in an Extra-Early Maturing Yellow Maize Population

“…The distribution of measured traits in the F 2:3 population indicated the existence of transgressive segregation (i.e., progenies performing outside the range of the parental genotypes). Transgressive segregation has been observed in populations screened under low N [65] and Striga infestation [66,67]. This phenomenon results from the accumulation of favorable and unfavorable alleles resulting from both parents.…”

Genetic analysis of prolificacy in “Sikkim Primitive”—A prolific maize (Zea mays) landrace of North‐Eastern Himalaya

“…Tiwari et al () analysed total carotenoids in maize through generation mean analysis, and found presence of 3–4 major gene blocks. Mbogo et al () identified one major gene block for striga resistance and three major gene blocks for plant height in maize. Chakraborti et al () reported 3–4 major gene blocks for kernel iron in maize.…”

“…The duplicate epistasis as identified in the study also indicated that alleles contributed by both the parents nullify the effects leading to lower degree of prolificacy. Mbogo, Dida, and Owuor (2015) also reported duplicate epistasis as an important factor for resistance to Striga hermonthica in maize. In the present study, however dominance × dominance [l] gene interaction was significant and positive across crosses and locations which infer that prolificacy can be effectively utilized in generating hybrids having multiple ears.…”