Heritability and Genes Governing Number of Seeds per Pod in West African Okra Abelmoschus caillei (A. Chev.) Stevels.

Heritability and genetic action moderating the inheritance of number of seeds per pod was investigated in four crosses of West African Okra accessions. Parents with variation for number of seeds per pod were used in hybridization process. Generations developed (Parents, F1, F2, BC1 and BC2) were planted for evaluation in a randomized complete block design with four replications. The results showed the adequacy of the additive – dominance model for one out of the four crosses (Acc6 x Acc1) and the inadequacy of the model for the remaining crosses. This was ascribed to significant estimates of A, B and C scaling test. The results of the generation mean analysis indicated that the additive genetic effect (d) significantly accounted for a large proportion of variability observed for number of seeds per pod in the crosses evaluated. The narrow sense heritability estimates were moderately high in all the crosses. An additive genetic effect suggests that selection among the segregating population could provide an average improvement in the performance of seed yield in subsequent generations. Keywords: West African Okra, Additive gene action, Generation means, Seed yield, Heritability, Genetic components

GGE BIPLOT APPLICATION FOR ADAPTABILITY OF AFRICAN YAM BEAN GRAIN YIELD TO FOUR AGRO-ECOLOGIES IN NIGERIA

Genotypes respond to environments differently; therefore it is important that their response to growing environment should be investigated in order to identify most suitable genotype(s) for specific environment. The objective of this study was to understand the adaptability of some accessions of African yam bean to different agro-ecologies of Nigeria. Thirty African yam bean (AYB) ( Sphenostylis stenocarpa (Hochst ex. A. Rich) Harms) accessions were evaluated for grain yield adaptability to four agro-environments in Nigeria. Genotype by environment (GE) interaction was significant (P < 0.01) for grain yield, with a range of 239.29 kg ha-1 (TSs 89) to 4130.46 kg ha-1 (TSs 33). Two principal component axes generated in the biplots explained 70.9% of the total variation due to the accessions and their interaction with the environments. The superior genotypes for each location were TSs82 (Ibadan), TSs116 (Mokwa), TSs24 (Ikenne) and TSs33 (Ubiaja). Three mega-environments arose from the study; namely Ikenne, Ubiaja and Mokwa (Ibadan merged with Mokwa to form a single mega-environment). Ikenne was a more representative environment for AYB production, having a mean grain yield of 1074.53 kg ha-1, closest to the grand mean of 1075.57 kg ha-1. However, Ubiaja was most supportive for grain production of AYB. Some of the accessions identified with high yielding, adaptable/stable in the study included TSs101, TSs111, TSs93, TSs94, TSs57, TSs104B and TSs109.Les g\ue9notypes r\ue9pondent diff\ue9remment aux environnements, donc il importe que leur r\ue9ponse \ue0 l\u2019environnement de production soit investigu\ue9e dans le but d\u2019identifier les g\ue9notypes appropri\ue9s \ue0 l\u2019environnement sp\ue9cifique. L\u2019objectif de cette \ue9tude \ue9tait de comprendre l\u2019adaptabilit\ue9 de quelques accessions du pois tub\ue9reux africain aux diff\ue9rentes agro-\ue9cologies du Nig\ue9ria. Trente accessions du pois tub\ue9reux africain (AYB) ( Sphenostylis stenocarpa (Hochst ex. A. Rich) Harms) \ue9taient \ue9valu\ue9es pour l\u2019adaptabilit\ue9 du rendement en graines \ue0 quatre agro-environnements au Nig\ue9ria. L\u2019interaction du g\ue9notype avec l\u2019environnement (GE) \ue9tait significative (P < 0,01) pour le rendement en graines, avec une marge de 239,29 kg ha-1 (TSs 89) \ue0 4130,46 kg ha-1 (TSs 33). Les deux axes de composantes principales g\ue9n\ue9r\ue9s dans les biplots, ont expliqu\ue9 70,9% de la variation totale due aux accessions et \ue0 leur interaction avec les environnements. Les g\ue9notypes sup\ue9rieurs pour chaque location \ue9taient TSs82 (Ibadan), TSs116 (Mokwa), TSs24 (Ikenne) et TSs33 (Ubiaja). Trois m\ue9ga-environnements \ue9taient obtenus dans l\u2019\ue9tude\ua0; \ue0 savoir Ikenne, Ubiaja et Mokwa (Ibadan s\u2019est fusionn\ue9 avec Mokwa pour former un simple m\ue9ga-environnement). Ikenne \ue9tait un environnement plus repr\ue9sentatif pour la production de AYB, en ayant un rendement moyen en graines de 1074,53 kg ha-1, proche du plus grand rendement moyen de 1075,57 kg ha-1. N\ue9anmoins, Ubiaja \ue9tait plus favorable pour la production en graines de AYB. Les quelques accessions identifi\ue9es avec un rendement \ue9lev\ue9, adaptable/stable dans cette \ue9tude comprennent: TSs101, TSs111, TSs93, TSs94, TSs57, TSs104B et TSs109

Correlation and path coefficient analysis of top-cross and three-way cross hybrid maize populations

Open Access JournalGrain yield is a complex quantitative trait that depends on a number of other traits for selection. This study was carried out to reveal the pattern of association with and contribution of traits to grain yield in two maize populations evaluated in three agro-ecological zones of South-Western Nigeria during the 2014 cropping season. The experiment consisted of 10 top-cross and 10 three-way cross maize hybrids, laid out in a randomised complete block design with three replications. Genotypic and phenotypic correlation coefficients and path co-efficient analyses were performed for each hybrid population across the three locations. Results showed significant (p≤0.05) differences between the two hybrid populations for all the traits mentioned except days to 50% anthesis, ear diameter and 100-grain weight. Field weight in both hybrid populations, number of kernel rows per cob, ear diameter and ear height in top-cross hybrids, as well as ear length and 100-grain weight in the three-way cross hybrids were directly correlated with grain yield. The link between direct and indirect effects on grain yield depends on hybrid population, although some traits showed similar direct effects in both hybrid populations. These traits can be used as the main criteria for grain yield improvement in the respective hybrid populations

Differential grain yield performance of single cross hybrid maize in varied nitrogen conditions

Presence of genotypic differences in maize ( Zea mays L.) grain yield in multi-environments would help plant breeders to make logical decisions in improvement programmes of the crop. Hence, the grain yield performance, heterosis and stability in hybrid maize in varied soil nitrogen (N) conditions in Nigeria were assessed using multiple biometrical techniques. Grain yield performance, heterosis and stability of 150 single cross hybrid maize were assessed with checks in severe N stress, N stress and optimal conditions in a replicated trial laid out in 19 7 8 lattice design for 2 years. The grain yield was subjected to analysis of variance for each N condition and combined across years. Heterosis was estimated for the trait, additive mean effects and multiplicative interaction (AMMI); and genotype + genotype 7 environment (GGE) models were used to analyse the hybrids\u2019 yield stability. The AMMI captured 93.7%; while GGE bi-plot accounted for 88.7% of total variation among the hybrids. Eight hybrids had high yields across the N conditions. Genotypes and environments affected heterosis for grain yield. Hybrids TZEI7 7BD74-399, BD74-179 7BD74-55 and BD74-175 7BD74-147 were the most ideal genotypes for the N conditions; while severe N stress condition was ideal test environment. Hybrid BD74-170 7BD74-31 adapted most to N stress; while TZEI1 7BD74-399 adapted most to severe N stress and to optimal conditions. Based on yield, heterosis and stability, hybrids involving inbred line BD74-171 were recommended for N stress; while those with inbred lines TZEI1, TZEI4 BD74-170, BD74-128, BD74-179 and BD74-175 were adapted to N stress and optimal conditions.La pr\ue9sence de diff\ue9rences g\ue9notypiques dans le rendement en grains de ma\uefs ( Zea mays L.) dans plusieurs environnements aiderait les selectioneurs \ue0 prendre des d\ue9cisions logiques dans les programmes d\u2019am\ue9lioration de ma\uefs. Par cons\ue9quent, les performances de rendement en grain, l\u2019h\ue9t\ue9rosis et la stabilit\ue9 d\u2018 hybride de ma\uefs dans les diverses conditions d\u2019azote (N) du sol au Nig\ue9ria ont \ue9t\ue9 \ue9valu\ue9es \ue0 l\u2019aide de multiples techniques biom\ue9triques. La performance de rendement en grain, l\u2019h\ue9t\ue9rosis et la stabilit\ue9 de 150 des hybrides de ma\uefs simples crois\ue9s ont \ue9t\ue9 \ue9valu\ue9s avec des contr\uf4les du stress grave en N, du stress en N et des conditions optimales dans le cadre d\u2019un essai r\ue9p\ue9t\ue9 pr\ue9sent\ue9 sur un r\ue9seau 19 7 8 pendant 2 ans. Le rendement en grains a \ue9t\ue9 soumis \ue0 une analyse de variance pour chaque condition d\u2019azote et combin\ue9 sur plusieurs ann\ue9es. L\u2019h\ue9t\ue9rosis a \ue9t\ue9 estim\ue9e pour le trait, les effets moyens additifs et l\u2019interaction multiplicative (MAIM); et des mod\ue8les g\ue9notype + g\ue9notype 7 environnement (GGE) ont \ue9t\ue9 utilis\ue9s pour analyser la stabilit\ue9 du rendement des hybrides. Le MAIM a captur\ue9 93,7%; alors que les bi-parcelles GGE ont repr\ue9sent\ue9 88,7% de la variation totale parmi les hybrides. Huit hybrides ont eu des rendements \ue9lev\ue9s dans les conditions d\u2019azote (N) du sol. Les g\ue9notypes et les environnements ont affect\ue9 l\u2019h\ue9t\ue9rosis pour le rendement en grain. Les hybrides TZEI7 7 BD74-399, BD74-179 7 BD74-55 et BD74-175 7 BD74-147 \ue9taient les g\ue9notypes les plus id\ue9aux pour les conditions N; tandis que la condition de stress N grave \ue9tait l\u2019environnement de test id\ue9al. Les hybrides BD74-170 7 BD74-31 \ue9taient les mieux adapt\ue9s au stress N; TZEI1 7 BD74-399 \ue9taient plus adapt\ue9s \ue0 l\u2018 intense stress li\ue9 \ue0 l\u2019azote et aux conditions optimales. En se basant sur le rendement, l\u2019h\ue9t\ue9rosis et la stabilit\ue9, des hybrides impliquant la lign\ue9e consanguine BD74-171 ont \ue9t\ue9 recommand\ue9s pour le stress sous N; tandis que ceux avec des lign\ue9es consanguines TZEI1, TZEI4 BD74-170, BD74-128, BD74-179 et BD74-175 ont \ue9t\ue9 adapt\ue9s au stress N et \ue0 des conditions optimales

RELATIVE DISCRIMINATING POWERS OF GGE AND AMMI MODELS IN THE SELECTION OF TROPICAL SOYBEAN GENOTYPES

Selection of crops is preceded by multi-locational testing in plant breeding; however, it becomes difficult for breeders to determine which genotypes should be selected in the presence of genotype by environment (GEI). Six genotypes of soybean ( Glycine max (L.) Merr.) were evaluated at ten locations in Nigeria for grain yield and stability. The analysis of variance revealed significant (P 640.05) GEI effect. Mean grain yield of the soybean genotypes ranged from 1148 kg ha-1 for genotype M351 to 1584 kg ha-1 for TGx 1448-2E. Ilorin in the southern guinea savanna of Nigeria was the most variable with high interaction principal component axes (IPCA); while Bauch in the northern guinea savanna was identified as more stable location in evaluating the soybean genotype. Mega-environments and the best yielding soybean genotypes in each mega-environment were revealed by the GGE biplot analysis. Furthermore, TGx 1448-2E and TGx 1440-1E, were established as the most promising, and stable genotypes across the test locations. Stability model of GGE biplot was superior, effective and informative in mega-environment analysis compared to AMMI analysis.La s\ue9lection des cultures est pr\ue9c\ue9d\ue9e de tests multilocaux en am\ue9lioration des plantes; cependant, il appara\ueet difficile pour les am\ue9liorateurs de d\ue9terminer quels types de g\ue9notypes s\ue9lectionner en pr\ue9sence du g\ue9notype x environnement (GEI). Six g\ue9notypes du Soja ( Glycine max (L.) Merr.) \ue9taient \ue9valu\ue9s dans dix milieux au Nigeria pour le rendement en grains et la stabilit\ue9. L\u2019analyse de la variance a r\ue9v\ue9l\ue9 un effet significatif (P 64 0.05) du GEI. Le rendement moyen en grains des g\ue9notypes du soja variait de 1148 kg ha-1 pour le g\ue9notype M351 \ue0 1584 kg ha-1 pour TGx 1448-2E. Ilorin au sud de la savanne guin\ue9enne au Nigeria \ue9tait le plus variable avec une interaction \ue9lev\ue9e des axes de la composante principale (IPCA); pendant que Bauch dans le nord de la savanne guinn\ue9enne \ue9tait identifi\ue9 comme milieu le plus stable dans l\u2019\ue9valuation du g\ue9notype du soja. Les Mega-environments et le meilleur g\ue9notype du soja du point de vue rendement dans chaque mega-environment \ue9taient r\ue9v\ue9l\ue9s par l\u2019analyse du biplot. En plus, TGx 1448-2E et TGx 1440-1E, \ue9taient jug\ue9s les plus promettants et g\ue9notypes stables \ue0 travers le test de milieu. Le mod\ue8le de stabilit\ue9 du biplot GGE \ue9tait sup\ue9rieur, effective et informative dans l\u2019analyse m\ue9ga-environmentale en comparaison avec l\u2019analyse du AMMI

Influence of environment on protein and oil contents of soybeans seed (Glycine Max (L.) Merril)

An attempt was made to study the magnitude of environmental variability on protein and oil contents of six genetically diverse soybean genotypes under three environments represented by three locations in Nigeria (Zaria in Northern Guinea Savanna, Jos in Pseudo Savanna and Mokwa in Southern Savanna) for two years (1996 and 1997). Significant genotypic location and location x genotype x year effects were observed for protein content while genotypic and location x genotype effects were significant for oil contents. Significant genetic differences in protein content occurred among genotypes, locations and between years, whereas significant genotypic differences in oil content was observed. Bossier and TGX849-313D out yielded in protein content. Protein content in Mokwa and Zaria were higher than that of Jos while protein content in Year 2 (1997) was higher than Year 1 (1996). Oil content remained similar irrespective of location and year. Jos is in a dry cool environment compared with Mokwa which is humid and hot and Zaria which is dry and hot. Environmental factors exerted greater influence more on the protein content than oil content of tropical soybean seeds. High temperature tended to increase protein content with little or no effect on oil content. There was positive significant association between protein and oil contents under Jos environment in 1997 whereas the association was negatively significant under Mokwa environment. Therefore, selection for protein and oil contents among soybean genotypes for further improvement is possible due to large variability present. Variations in protein and oil contents were due to differences in location. Changes in climatic factors resulting from yearly cultivation of soybean in different locations can influence protein content. Key Words: correlation analysis, genotype, Glycine max, oil, protein [Global Jnl Agric Sci Vol.1(1) 2002: 27-32

Genetics evaluation of phosphorus utilization in tropical cowpea (Vigna unguiculata (L) Walp)

Genetics evaluation of phosphorus utilization in cowpea (Vigna unguiculata (L) Walp) was studied in a cross involving a tropically adapted genotype (IT90K-277-2) with a reported positive response to rock phosphate (RP) and a second genotype (IT89KD-288) that responds negatively to RP, using generation mean analysis of the parents, their F1 , F2 and the two backcross generations. Highly significant differences among the six generations with respect to seed phosphorus (P) concentration and grain yield per plant were observed. The F1 progenies produced seeds with higher seed P concentration (0.31 mg/g) than the mid-parent value (0.27mg/g). Mean yield per plant in the F1 (48.03g) that was significantly greater than the mid-parent value (28.85g) was also observed suggesting positive heterosis for the two traits. Backcrossing to both parents showed good convergence of genes on the recurrent parents. Possibility of transgressive segregation for seed P concentration and grain yield per plant in the F2 generation was also observed. Absence of significant reciprocal differences among individuals in the F1 and F2 populations suggested lack of maternal and cytoplasmic effects. Non-additive gene action (dominance and epistasis) made significant contributions to total genetic variations in both traits within the cross. Whereas seed P concentration was observed to be under polygenic control, number of genes for seed yield per plant was biased downward by epistasis. Observed narrow-sense heritability estimate (HN)) for seed P concentration of 50.51% and very low (0.040) expected genetic gain in the F3 over the F2 means suggested that although expected progress from selection could be lowered by non-additive gene effects, this trait could be transmitted to the offsprings of hybridization program with huge success, through backcrossing. Although, available soil P (6.03 –8.09mg/kg) was observed to be below the critical level, phosphorus uptake in the F1 and the segregating generations was observed to be higher than what obtained in the parents to suggest that the progenies of a P-efficient x P-inefficient cross would be efficient in P utilization

Comparative studies on the yield of some herbaceous legumes and effects of storage on the quality of their pellets

Dry matter yield of herbaceous legumes and effects of storage length of their pellets on the chemical composition were investigated. A two phased field and laboratory experiment were conducted. In the first experiment, the yield of the forage legumes using a 5 x 2 factorial experiment consisting of five herbaceous legumes (Lablab purpureus, Mucuna pruriens, Centrosema molle, Centrosema pascorum and Calopogonium mucunoides) and two harvesting ages (6 and 12 weeks after sowing) laid out in a split-plot design was determined. The second experiment was the selection of herbaceous legumes with higher yields from Experiment 1 using a 3 x 4 factorial experiment consisting of the three herbaceous legumes (L. purpureus, C. mucunoides and M. pruriens) used to make pellets and four storage lengths (0 i.e. fresh, 30, 60 and 90 days). Treatments in both experiments were replicated three times. Results showed that legumes harvested 12 weeks after sowing (WAS) had significantly (P < 0.05) higher dry matter yield (2.73 t ha-1) than legumes at 6 WAS, while Lablab purpureus produced the highest (P < 0.05) dry matter yield (2.94 t ha-1) of the legumes evaluated.. The physical characteristics of the herbaceous legumes pellets such as colour, odour and moldiness at different storage length showed that they were between fair and good pellets. The L. purpureus and M. pruriens had higher (P < 0.05) CP content than C. mucunoides. Differences in the CP content of pellets with the storage lengths employed was not significant (P > 0.05). Higher oxalate, phytate and saponin contents were found in C. mucunoides pellets than in other legumes pellets while the tannin content was in the order of M. pruriens (43.63 mg kg-1) > L. purpureus (26.00 mg kg-1) > C. mucunoides (20.31 mg kg-1). In conclusion, increasing age at harvest increased the yield of the legumes, while increasing storage duration decreased the CP content but increased the NDF, ADF and saponin content of the pellets

Heterotic grouping of tropical maize inbred lines and their hybrid performance under stem borer infestation and low soil nitrogen condition in west and central Africa

Published online: 03 Jan 2021Low soil nitrogen (low-N) and stem borer attack are two of the major stresses limiting maize production in West and Central Africa (WCA). Thus, there is need to intensify efforts aimed at identifying inbred lines with resistance and tolerance to these stresses for hybrid development. The objectives of the study were to determine the combining ability of maize inbred lines, classify them into heterotic groups using both conventional and marker-based approaches, compare the efficiency of the different grouping methods and evaluate the performance of the hybrids generated from the inbred lines under contrasting environments. Ten white maize inbred lines with varying levels of resistance to stem borers were selected and crossed in a diallel in 2015. The resulting 45 hybrids were evaluated together with five checks in 10 environments under low-N, artificial stem borer infestation and non-stress conditions in Nigeria. General combining ability (GCA) and specific combining ability (SCA) were highly significant (p ≤ 0.01) for most of the traits studied but GCA was predominant over SCA under each and across research conditions. Inbred line 2 combined significant positive GCA for grain yield with significant negative GCA for traits of resistance to stem borers and tolerance to low-N. Each of the grouping methods classified the inbred lines into 3 heterotic groups but SCA and heterotic groups’ specific and general combining ability had the joint highest breeding efficiency. Hybrids 1 × 4, 2 × 3, 1 × 6 and 2 × 5 were identified to be high yielding and stable across environments and can serve as candidates for further on-farm evaluations and eventual release in WCA