Genetic Analysis of Agronomic Traits in Barley (Hordeum vulgare L.)Landrace Lines under Drained and Waterlogged Conditions

Estimates of genetic parameters are useful to predict the breeding values of genotypes that will help to make effective crosses. This study was  undertaken to estimate genetic parameters and determine the breeding values of barely landrace lines waterlogged and drained conditions. Two sets of  experiments each consisting of five landrace lines and 10 F1 crosses generated in diallel mating were established in a greenhouse at the University of the  Free State, South Africa. Analysis of variance showed significant variations among genotypes for most studied traits under drained experiment but non-  significant variation for most traits under waterlogging. As compared to the drained experiment, waterlogging reduced grain yield and number of  productive tillers; and delayed days to heading and maturity. General combining ability (GCA) mean squares were significant for most traits, whereas  mean squares for specific combining ability (SCA) were significant only for few traits. Additive gene action was found to be important for days to heading  and maturity while both additive and non-additive gene effects were important in conditioning spike length under both drained and waterlogged  conditions. Under drained conditions, only additive gene action was important for seeds spike-1 and grain yield spike-1, while both additive and non-  additive gene effects were important in conditioning grain yield. The values of estimates of genetic parameters for yield and yield components (except  spike length) were very low under waterlogged conditions, indicating adverse effect of waterlogging stress on the expression of genetic effects. Among  the parental lines, Feres Gama(37) and 1153(28) showed high positive GCA effects for yield and yield components under drained condition Moge(07),  1182(44) and 1153(82) showed desirable GCA effects for early maturity. These parents could be extensively used in future breeding programs to develop  crosses with higher grain yield and desirable agronomic traits. None of the inbred lines showed desirable GCA effects for grain yield and most other yield  related traits under waterlogged condition, indicating the need for further research with increased number of lines to identify the ones with better  combining ability

HETEROTIC PERFORMANCE OF QUALITY CHARACTERISTICS OF BREAD WHEAT CULTIVARS

Heterosis has made a significant contribution to the improvement of many crops regarding yield, quality and resistance to pests. The low wheat ( Triticum aestivum L.) productivity in Lesotho has necessitated exploitation of heterosis in commercial cultivars. Heterotic performance of 38 F1 and F2 progenies from 5 x 5 diallel crosses of wheat cultivars were estimated for mid-parent and best-parent values. There were significant differences between F1 and F2 progenies for all characteristics. In F1 progeny, a positive mid-parent heterosis was observed in Sodium dodecyl sulphate (SDS) sedimentation volume, kernel hardness, break flour yield and kernel weight. Positive best-parent heterosis was obtained in all the above parameters. In F2 progeny, characteristics that showed positive mid-parent heterosis were mixograph development time, hardness index and SDS sedimentation volume; while positive best-parent heterosis was observed in mixograph development time, hardness index, kernel diameter and weight. A significant increase in mid-parent heterosis was observed for five characteristics in Sceptre x Wanda and SST124 x Nata. Another significant increase in mid-parent heterosis occurred for four characteristics in Nata x Wanda, Nata x Sceptre, Sceptre x Kariega, Sceptre x SST 124, Wanda x SST 124 and Sceptre x Nata. SST 124 x Sceptre, Nata x Wanda, SST 124 x Kariega and Kariega x Nata revealed a significant increase in best-parent heterosis for all characteristics.L\u2019h\ue9terosis a significativement contribu\ue9 \ue0 l\u2019am\ue9lioration de beaucoup de cultures en terme de rendement, qualit\ue9 et r\ue9sistance aux pestes. La basse productivit\ue9 du bl\ue9 ( Triticum aestivum L.) au Lesotho a n\ue9cessit\ue9 l\u2019exploitation de l\u2019h\ue9terosis dans les cultivars commerciaux. La performance h\ue9terotique de 38 F1 et prog\ue9nies F2 \ue0 partir des croisements des cultivars de bl\ue9 diall\ue8les 5 x 5 \ue9taient estim\ue9e pour des valeurs des parents moyens et meilleurs parents. Des diff\ue9rences singnificatives \ue9taient observ\ue9es entre les prog\ue9nies F1 et F2 pour toutes les caract\ue9ristiques. Dans la prog\ue9nies F1, une h\ue9terosis positive du parent moyen \ue9tait observ\ue9e dans le volume de s\ue9dimentation de Sulfate dodecyl de Sodium (SDS), la duret\ue9 de grains, le rendement en farine, le rendement et le poids de grains. L\u2019h\ue9terosis de meilleurs parents \ue9tait obtenue dans tous les param\ue8tres ci-dessus. Dans la prog\ue9nie F2, caract\ue9ristiques qui ont manifest\ue9 l\u2019h\ue9terosis positive des parents moyens \ue9tait un temps de d\ue9veloppement der mixographe, l\u2019indice de duret\ue9 et le volume de s\ue9dimentation SDS; pendant que l\u2019h\ue9terosis positive de meilleurs parents \ue9tait observ\ue9e dans le temps de d\ue9veloppement du mixographe, l\u2019indice de duret\ue9, le diam\ue8tre et le poids de grains. Une augmentation significative dans l\u2019h\ue9terosis des parents moyens \ue9tait observ\ue9e pour cinq caract\ue9ristiques dans Sceptre x Wanda et SST124 x Nata. Une autre augmentation dans l\u2019h\ue9terosis des parents moyens \ue9tait observ\ue9e pour quatres caract\ue9ristiques dans Nata x Wanda, Nata x Sceptre, Sceptre x Kariega, Sceptre x SST 124, Wanda x SST 124 et Sceptre x Nata. SST 124 x Sceptre, Nata x Wanda, SST 124 x Kariega et Kariega x Nata ont r\ue9v\ue9l\ue9 une augmentation sugnificative dans l\u2019h\ue9terosis de meilleurs parents pour toutes les caract\ue9ristiques

ESTIMATES OF GENETIC PARAMETERS FOR QUALITY OF WHEAT CULTIVARS GROWN IN LESOTHO

Lesotho has embarked on wheat ( Triticum aestivum ) improvement programmes that increase productivity and quality. Among these is selection of superior genotypes. A study was conducted to estimate genetic variance, heritability, dominance, correlation and prediction ratio for wheat quality characteristics of five parents, F1 and F2 progeny. The characteristics were break flour yield, flour protein content, mixograph development time, Sodium Dodycel Sulphate sedimentation volume, kernel weight, kernel diameter and kernel hardness. General specific combining ability ratio in F1 progeny showed non-additive gene action in all characteristics except one. In F2 progeny, break flour yield, flour protein content, kernel hardness and mixograph development time were controlled by non-additive gene action. Sodium Dodycel Sulphate sedimentation volume, kernel weight and kernel diameter were controlled by additive gene action. Heritability in the broad sense was high for all characteristics in F1 and F2 progeny, whereas heritability in the narrow sense was high for F2 and low for F1 progeny. Positive and negative correlations were observed among characteristics in F1 and F2 progeny. In F1 progeny, kernel hardness demonstrated highest prediction ratio. In F2 progeny, seed diameter, seed weight, Sodium Dodecyl Sulphate sedimentation volume and break flour yield revealed high prediction ratio. Genetic variability exists and can be for improvement of wheat quality in Lesotho.Le Lesotho a embarqu\ue9 sur des programmes d\u2019am\ue9liorations du bl\ue9 ( Triticum aestivum ), entre autre la s\ue9lection des g\ue9notypes \ue0 traits sup\ue9rieurs, afin d\u2019accro\ueetre la productivit\ue9 et la quali\ue9 du bl\ue9. Une \ue9tude \ue9tait conduite pour estimer la variance g\ue9n\ue9tique, l\u2019h\ue9ritabilit\ue9, la dominance, la correlation et le taux de pr\ue9diction des caract\ue9ristiques de qualit\ue9 de cinq parents, les prog\ue9nies F1 et F2. Les dites caract\ue9ristiques \ue9taient le rendement en farine, le contenu prot\ue9nique de la farine, le temps de d\ue9veloppement du mixographe, le volume de s\ue9dimentation du sulfate de sodium Dodycel, le poids de grains, le diam\ue8tre et la duret\ue9 des grains. Le rapport de la capacit\ue9 de combinaison g\ue9n\ue9rale de la prog\ue9nie F1 a montr\ue9 une action de g\ue8ne non additif dans toutes les caract\ue9ristiques except\ue9e une seule. Dans la prog\ue9nie F2, le rendement en farine, le contenu prot\ue9inique de la farine, la duret\ue9 des grains et le temps de d\ue9veloppement du mixographe \ue9taient contr\uf4l\ue9s par une action de g\ue8ne non additif. Par contre, le volume de s\ue9dimentation du sulfate de sodium Dodecyl, le poids et le diam\ue8tre de grains \ue9taient contr\uf4l\ue9s par un g\ue8ne additif. L\u2019h\ue9ritabilit\ue9 au sens large \ue9tait \ue9lev\ue9 pour toutes les caract\ue9ristiques dans les prog\ue9nies F1 et F2. Des correlations positives and n\ue9gatives \ue9taient observ\ue9es parmi les caracteristiques dans les prog\ue9nies F1 et F2. Dans F1, la duret\ue9 de grains a d\ue9montr\ue9 un rapport de pr\ue9diction plus \ue9lev\ue9. Dans F2, le diam\ue8tre de grains, le poids de grains, le volume de s\ue9dimentation du Sulfate de Sodium Dodecyl et le rendement en grains ont r\ue9v\ue9l\ue9 un niveau du rapport de pr\ue9diction \ue9lev\ue9. La variabilit\ue9 g\ue9n\ue9tique existe et peut servir dans l\u2019am\ue9lioration de la qualit\ue9 du bl\ue9 au Lesotho

PREDICTION OF BREAD-MAKING QUALITY USING SIZE EXCLUSION HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Variation in the distribution of protein molecular weight in wheat ( Triticum aestivum ), influences breadmaking quality of wheat cultivars, resulting in either poor or good bread. The objective of this study was to predict breadmaking quality of wheat cultivars using size exclusion high performance liquid chromatography. Seeds from twenty F1 and F2 progeny, and their parents were used. A procedure was followed involving extraction by Sodium Dodecyl Sulphate (SDS), followed by sonication to remove remaining proteins. A computer software Chromsword developed by Shimadzu Corporation was used to estimate different protein classes, after which data were generated from chromatogram. The highest Glutenin/Gliadin (GG) ratio in SDS-soluble and insoluble protein fractions in F1 progeny, were obtained from Wanda x Sceptre and Nata x SST 124 cultivars, respectively. In F2 progeny, the cultivar with the highest G/G ratio in SDS soluble protein fractions was Kariega x SST124. Cultivars with high G/G ratios in SDS-insoluble protein fraction were Sceptre x Nata and Kariega x Sceptre. The ratios of high molecular weight/low molecular weight glutenin sub-units (HMW/LMW-GS) in both SDS-soluble and insoluble protein fractions were comparable in F1 progeny with little variation among cultivars. In F2 progeny, Kariega x SST 124 led in high HMW-GS/LMW-GS ratio. The highest ratio of polymeric/monomeric protein in both F1 and F2 progeny was obtained from Nata x Sceptre in both generations. Therefore, most wheat cultivars revealed high breadmaking quality.La variation dans la distribution du poids mol\ue9culaire de prot\ue9ines dans le bl\ue9 ( Triticum aestivum ), influence la qualit\ue9 panifiable des cultivars du bl\ue9, r\ue9sultant en un pain pauvre ou bon. L\u2019objectif de cette etude \ue9tait de pr\ue9dire la qualit\ue9 panifiable des cultivars de bl\ue9 en utilisant un liquide chromatographique de performance \ue9lev\ue9e d\u2019exclusion de taille. Les grains de vingt prog\ue9nies F1 et F2 et leurs parents \ue9taient utilis\ue9s. La proc\ue9dure consistait en une extraction par le Sulphate Dodecyl de Sodium (SDS), suivi par sonication pour enlever les prot\ue9ines restantes. Un ordinateur de logiciel Chromsword d\ue9velopp\ue9 par l\u2019Entreprise Shimadzu \ue9tait utilis\ue9 pour estimer diff\ue9rentes classes de prot\ue9ines, apr\ue8s lesquelles les donn\ue9es \ue9taient g\ue9n\ue9r\ue9es du chromatogramme. Le rapport le plus \ue9lev\ue9 Glutenin/Gliadin (GG) dans les SDS-soluble et les fractions de prot\ue9ines insolubles dans la prog\ue9nie F1 \ue9tait obtenu des cultivars Wanda x Sceptre et Nata x SST, respectivement. Dans la prog\ue9nie F2, le cultivar avec le rapport le plus \ue9lev\ue9 G/dans les fractions de prot\ue9ines SDS soluble \ue9tait Kariega x SST124. Les cultivars avec des rapports \ue9lev\ue9s G/G dans la fraction de prot\ue9ine insoluble SDS \ue9taient Sceptre x Nata et Kariega x Sceptre. Les rapports du poids mol\ue9culaire \ue9lev\ue9 sur le poids mol\ue9culaire bas des sous unit\ue9s de la glutenine (HMW/LMW-GS) dans le SDS-Soluble et les fractions de prot\ue9ines insolubles \ue9taient comparables dans la prog\ue9nie F1 avec une petite variation parmi les cultivars. Dans F2, Kariega x SST 124 donn\ue9 un rapport HMW-GS/LMW-GS \ue9lev\ue9. Le rapport le plus \ue9lev\ue9 des prot\ue9ines polymerique/monomerique dans les prog\ue9nies F1 et F2 \ue9tait obtenu de Nata x Sceptre dans toutes les deux generations. Par cons\ue9quent, laplupart des cultivars de bl\ue9 ont r\ue9v\ue9l\ue9 une qualit\ue9 panifiable \ue9lev\ue9e

Heritability and expression of selected mixograph parameters in progeny of parents varying for mixing time

The mixograph performs certain rheological measurements during dough mixing and is a good predictor of wheat end-use quality. The aim of this study was to determine the expression and the heritability of mixing characteristics measured with Mixsmart® software and some quality characteristics in hard red spring wheat parents and their F1 progeny. Six parents varying in midline peak time and envelope peak time were crossed in a half diallel design. Parents and progeny were planted in three different environments. General combining ability (GCA) was a significant source of variation for the measured characteristics, and parents differed widely in terms of GCA effects. Midline-development time, -peak integral and -peak time showed high narrow sense heritability. Envelope peak-integral and -tail width displayed high narrow sense heritability for some, but not all locations. High GCA:SCA (specific combining ability) ratios indicated the prevalence of additive gene effects for midline-development time, -peak integral and -peak time, indicating that these characteristics are largely genetically determined, and that selection for them should lead to genetic gain

Allelic variation Of HMW glutenin subunits Of Ethiopian bread wheat cultivars and their quality

High molecular weight glutenins are often effective in identifying wheat ( Triticum aestivum ) genotypes with good baking quality. The high molecular weight glutenin subunit composition of Ethiopian cultivars and advanced lines was investigated to determine their influence on quality. Three alleles at Glu-A1, five at Glu-B1 and two at Glu-D1 and eleven different banding patterns were identified. Few cultivars had biotypes at Glu-A1 and Glu-D1 loci. There were highly significant differences between genotypes and banding patterns for the SDS-sedimentation test, mixograph development time, alveograph strength and loaf volume; but not for protein content. The frequency of subunits 5+10 among genotypes was 73%. The accumulation of high scoring alleles in our germplasm was without deliberate selection pressure towards high Glu-1 scoring alleles during breeding. Introductions from CIMMYT are widely used and such materials might have gone through selection and accumulation of such alleles at CIMMYT. Most of the studied materials had the required subunits of high quality scores and better values of the quality traits than originally thought. Therefore, the concern about poor baking quality is unlikely to be due to Glu-1 allelic variations alone.Le poids mol\ue9culaire \ue9lev\ue9 des glutanines est souvent un moyen efficace pour identifier les g\ue9notypes du bl\ue9 ( Triticum aestivum ) dot\ue9 de bonnes qualit\ue9s patissi\ue8res. Une investigation \ue9tait faite sur le poids mol\ue9culaire \ue9lev\ue9 des glutanines des sous unit\ue9s des cultivars \ue9thiopiens ainsi que sur des lign\ue9es avanc\ue9es pour d\ue9terminer leur influence sur la qualit\ue9. Trois all\ue8les \ue0 Glu-A1, cinq \ue0 Glu-B1 et deux \ue0 Glu-D1 ainsi que onze diff\ue9rents modes de bandage \ue9taient identifi\ue9s. Peu de cultivars avaient des biotypes \ue0 Glu-A1 et Glu-D1 loci. Une diff\ue9rence hautement significative \ue9tait observ\ue9e entre g\ue9notypes et modes de bandage pour le test de s\ue9dimentation SDS, le temps de d\ue9veloppement de mixographe, la force de l'alv\ue9ographe et le volume du pain mais non au contenu en prot\ue9ines. La fr\ue9quence des sous unit\ue9s 5+10 parmi les g\ue9notypes \ue9tait 73%. L'accumulation des all\ue8les \ue0 score plus \ue9lev\ue9 dans notre germoplasme avait eu lieu sans s\ue9lection d\ue9lib\ue9r\ue9e de la pression des all\ue8les \ue0 score plus \ue9lev\ue9 en Glu-1 pendant le breeding. Des introductions de CIMMYT sont largement utilis\ue9es et de tels mat\ue9riels devraient passer par la s\ue9lection et l'accumulation de telles all\ue8les au CIMMYT. La plupart des mat\ue9riels \ue9tudi\ue9s poss\ue9daient de sous unit\ue9s requises avec de scores de haute qualit\ue9 et meilleures valeurs de traits de qualit\ue9 qu'on ne le pensait originellement. Par cons\ue9quent, le probl\ue8me concernant la pauvre qualit\ue9 patissi\ue8re n'\ue9tait pas seulement d\ufb aux variations all\ue9liques Glu-1

Breeding implications of nodulation performance and root structure under natural inoculation for soil fertility enhancement and sustainable cowpea production

Open Access Journal; Published online: 08 Dec 2022Nitrogen deficiency is the most limiting abiotic stress factor affecting the grain yield of cowpea (Vigna unguiculata L.) in sub-Saharan Africa (SSA) countries. Breeding for high-yielding potential in association with high nitrogen fixation performance is the principal objective of cowpea breeding programs to improve both the productivity and production of this orphan crop in the region. Therefore, the present study was undertaken to determine the diversity of genotypes for nodulation capacity in two environments and to understand the root architecture and morphology of genotypes as well as grain yield and yield-related traits in 324 cowpea genotypes. The experiment was conducted in two different environments during the 2017 cropping season. The experiments were laid out in 18 × 18 simple lattice design. Grain yield exhibited highly significant and positive genotypic correlations with stem diameter, basal root length of 1st whorls, basal root branching density, taproot length and adventitious root length, demonstrating that selection of cowpea genotypes based on these traits could be effective to capitalize on grain yield under low nitrogen conditions. Days to flowering, days to maturity, stem diameter, 1st whorl angle, basal root length of 1st whorls, basal root branching density, taproot length, adventitious root diameter and adventitious root length had significant and positive genotypic correlations with days to maturity. The first ten principal components (PC) explained 65.13% of the total variation. Stem diameter, taproot width, and taproot length traits were important contributors to the variability in the first PC. The highest inter-cluster distance (D2) was recorded between clusters III and IV. However, clusters II and V recorded the minimum inter-cluster distance (78.96 units). The range of intra-cluster distance was 24.22–5,112.92 units, indicating that the high genetic distance displayed within and between clusters has to be exploited via crossing and selecting the most divergent parents for future cowpea improvement. Five clusters of cowpea genotypes were evident, and within the clusters, the genotypes had good nodulation potential with high grain yield traits, which could significantly contribute to SSA food and nutritional security. Moreover, it can contribute to resilience and improve crop production and sustainability under marginal environmental conditions

Genetic variation and trait associations of yield, protein and grain micronutrients for identification of promising sorghum varieties

Sorghum is, globally, the fifth most important cereal after maize, rice, wheat and barley. The crop is tolerant to semi-arid and arid climatic conditions. Twenty-five sorghum varieties grown in South Africa were evaluated in the field at two locations with the objective of identifying high yielding, micronutrient dense genotypes. Two clusters were formed based on measured traits. Tx430 (G13), CIMMYT entry 49 (G12), E35-1 (G16), Framida (G19), IS1934 (G7) and IS14380 (G14) formed cluster A. The rest of the sorghum entries formed cluster B. Wide variation was exhibited for grain yield, ranging from 1.12 t ha−1 to 3.96 t ha−1 with a mean grain yield of 2.83 tha−1. Analysis of variance also revealed significant differences among the varieties for protein, total starch, amylose and mineral content. Two varieties, Tx430 and AR-3048 exhibited very high protein content. Fe content ranged from 43.7 mg kg−1 (Kuyuma) to 61.2 mg kg−1 (IS14380) with an average of 50.5 mg kg−1. Zn content ranged from 13.7 mg kg−1 (Macia) to 23.4 mg kg−1 (Tx430) with a mean of 17.4 mg kg−1. Grain yield was significantly positively correlated with plant height, panicle weight and thousand kernel weight. Significant positive correlations were observed between Fe content and Zn, Cu, Mn and P. This data indicated that simultaneous genetic improvement of sorghum varieties for Fe and other important minerals, and starch content in the same genetic background was possible, without a penalty to grain yield

Inheritance of resistance to Fusarium verticillioides ear rot in maize inbred lines of southern, west and central Africa origin

Open Access Article; Published online: 22 Jul 2022Maize (Zea mays L.) is an important crop in sub-Sahara Africa for both human consumption and livestock feed. Maize use is often limited by ear-rotting fungi, some of which produce deleterious secondary metabolites. The aim of this study was to determine the inheritance of resistance to Fusarium verticillioides as an indirect way of selecting for resistance to secondary metabolites such as the mycotoxin fumonisin that is produced by this fungus, under artificial inoculation and natural infection. Twelve inbred lines from Seed Co that were used as the females, were mated to 12 tester lines from the International Institute of Tropical Agriculture (IITA) that were used as males, using the North Carolina Design II. The resulting 144 F1 hybrids and six check hybrids were evaluated in Zimbabwe. Artificial inoculation with F. verticillioides was done at Rattray Arnold Research Station in the first season. The general (GCA) and specific combining ability (SCA) effects for F. verticillioides incidence were variable across sites for the lines and the testers. Six southern African inbred lines had desirable GCA for F. verticillioides ear rot and can be used as resistance sources. Outstanding testers from IITA that had negative GCA for F. verticillioides ear rot and fumonisins were identified. Both additive and nonadditive effects were implicated in resistance to ear rot caused by F. verticillioides and potential lines were identified that can be used in regional breeding programs

Relationship between grain yield and quality traits under optimum and low-nitrogen stress environments in tropical maize

Breeding for nitrogen use efficiency (NUE) is important to deal with food insecurity and its effect on grain quality, particularly protein. A total of 1679 hybrids were evaluated in 16 different trials for grain yield (GY), grain quality traits (protein, starch and oil content) and kernel weight (KW) under optimum and managed low soil nitrogen fields in Kiboko, Kenya, from 2011 to 2014. The objectives of our study were to understand (i) the effect of low soil N stress on GY and quality traits, (ii) the relationship between GY and quality traits under each soil management condition and (iii) the relationship of traits with low-N versus optimum conditions. From the results, we observed the negative effects of low N on GY, KW and the percentage of protein content, and a positive effect on the percentage of starch content. The correlation between GY and all quality traits was very weak under both soil N conditions. GY had a strong relationship with KW under both optimum and low soil N conditions. Protein and starch content was significantly negative under both optimum and low-N conditions. There was no clear relationship among quality traits under optimum and low N, except for oil content. Therefore, it seems feasible to simultaneously improve GY along with quality traits under both optimum and low-N conditions, except for oil content. However, the negative trend observed between GY (starch) and protein content suggests the need for the regular monitoring of protein and starch content to identify varieties that combine both high GY and acceptable quality. Finally, we recommend further research with a few tropical maize genotypes contrasting for NUE to understand the relationship between the change in grain quality and NUE under low-N conditions