Selection For High Yield Research Articles

New flavors from old wheats: exploring the aroma profiles and sensory attributes of local Mediterranean wheat landraces.

During the 20th century, the worldwide genetic diversity of wheat was sharply eroded by continual selection for high yields and industry demands for particular standardized qualities. A collection of Israeli and Palestinian landraces (IPLR) was established to represent genetic diversity, accumulated for ten millennia under diverse environments, which was mostly lost in this transition. As our long-term goal is to study this pre- Green Revolution genetic reservoir, herein we focus on its flour and bread quality and sensorial attributes. Initially, a database was built for the entire IPLR collection (n=901) holding both Triticum durum (durum wheat) and T. aestivum (bread wheat) which included genetic and phenotypic characterization of agronomic traits, grain and flour quality. Then, a representative subset of the IPLR was selected and compared to modern varieties for dough quality, rheology, aroma and taste using both whole and refined flours and breads. The sensory panel used 40 subjects who evaluated common protocol or sourdough breads made by four artisan bakers. Results show modern durum cultivar C-9 had superior rheological properties (gluten index, elasticity, dough development time) as compared with landraces, while bread landrace 'Diar Alla' was markedly preferable for baking in relation to the modern cultivar Gadish. Baking tests and subsequent sensory evaluation clearly demonstrated a preference toward refined breads, apart from whole breads prepared using sourdough starters. In bread wheat, loaves baked using landrace flour were scored higher in several quality parameters, whereas in durum lines, the opposite trend was evident. Loaves baked from landraces 'Diar Alla' and to a lesser extent 'Hittia Soada' presented a markedly different aroma from the control loaves prepared from modern flours, both in terms of overall compositions and individual compounds, including classes such as pyranones, pyrazines, furans and pyrroles (maltol). Modern lines, on the other hand, were consistently richer in terpenes and phenylpropanoids. Further analysis demonstrated a significant association between specific aroma classes and sensory attributes scored by panelists. The findings of the study may help advance new niches in the local wheat market aimed at health and nutrition including adapting durum varieties to the bread market and developing flavor-enhanced wholemeal breads.

Analysis of the effect of GE interaction on the grain yield and its related traits in rain-fed Algerian durum wheat (Triticum turgidum L. var. durum) grown in contrasting environments

Selection for higher yield and wider adaptability are the most important tasks in crop breeding programs. (GE) interactions are commonly seen as one of the major barriers in plant breeding. The present work aims to assess the effects of GE interaction for the grain yield of 14 durum wheat varieties grown in rain-fed environments during 2014-2017 cropping seasons, and to analyze the relationships between 15 traits intra and inter-environments. Field trials were carried out in a randomized complete block design with four replicates. Grain yield data were analyzed using AMMI model. The combined analysis of variance showed that the effects of genotype, environment and their interactions were highly significant on the grain yield. Using CV and Pi index, GTA dur was the high yielding (32.5 q ha-1) and most stable variety across all the environments. Based on the inter-character correlation, the indirect selection of grain yield via the number of grains per m2 would be effective. Moreover, the inter-environment correlation of the studied variables confirms there was GE interaction and suggests that the best varieties should be chosen according to their specific adaptation. Cold environments differed from warm and moderate ones in the ranking of varieties. Indeed, Sétif site offers better possibilities for producing the Ofanto variety (39.9 q ha-1). Whereas, GTA dur and Simeto (30.9 q ha-1 and 29.7 q ha-1, respectively) prove to be the most efficient in terms of grain yield at Oued Smar and Khemis Miliana sites together.

Identification of quantitative trait loci (QTL) and meta-QTL analysis for kernel size-related traits in wheat (Triticum aestivum L.)

BackgroundKernel size-related traits, including kernel length (KL), kernel width (KW), kernel diameter ratio (KDR) and kernel thickness (KT), are critical determinants for wheat kernel weight and yield and highly governed by a type of quantitative genetic basis. Genome-wide identification of major and stable quantitative trait loci (QTLs) and functional genes are urgently required for genetic improvement in wheat kernel yield. A hexaploid wheat population consisting of 120 recombinant inbred lines was developed to identify QTLs for kernel size-related traits under different water environments. The meta-analysis and transcriptome evaluation were further integrated to identify major genomic regions and putative candidate genes.ResultsThe analysis of variance (ANOVA) revealed more significant genotypic effects for kernel size-related traits, indicating the moderate to high heritability of 0.61–0.89. Thirty-two QTLs for kernel size-related traits were identified, explaining 3.06%—14.2% of the phenotypic variation. Eleven stable QTLs were detected in more than three water environments. The 1103 original QTLs from the 34 previous studies and the present study were employed for the MQTL analysis and refined into 58 MQTLs. The average confidence interval of the MQTLs was 3.26-fold less than that of the original QTLs. The 1864 putative candidate genes were mined within the regions of 12 core MQTLs, where 70 candidate genes were highly expressed in spikes and kernels by comprehensive analysis of wheat transcriptome data. They were involved in various metabolic pathways, such as carbon fixation in photosynthetic organisms, carbon metabolism, mRNA surveillance pathway, RNA transport and biosynthesis of secondary metabolites.ConclusionsMajor genomic regions and putative candidate genes for kernel size-related traits in wheat have been revealed by an integrative strategy with QTL linkage mapping, meta-analysis and transcriptomic assessment. The findings provide a novel insight into understanding the genetic determinants of kernel size-related traits and will be useful for the marker-assisted selection of high yield in wheat breeding.

Genotype by environment interaction effect on some selected traits of orange-fleshed sweet potato (Ipomoea batatas [L].Lam)

In Ethiopia, sweet potato is the 2nd and the most important root crop after Enset [Ensete ventricosum (Welw) Cheesman]. Even though widely cultivated in Ethiopia, the occurrences of wide agro-ecological variability are the key challenge for the selection of high yield and stable orange-fleshed sweet potato genotypes due the high interaction of genotype by environment effect (GEI). Until to date, the research reports on GEI and stability of orange-fleshed sweet potato genotypes under Southwest and West of Ethiopian conditions is very limited. Due to this fact, the study was conducted in main sweet potato growing of Southwest and West of Ethiopia since the 2019-2020 growing seasons. Nine Orange-fleshed sweet potato genotypes were evaluated in four different ecologies in completely randomized block design with three replications. The mainly indicative data and related variables were collected and analyzed by using ANOVA, AMMI, and GGE biplots. The ANOVA for total storage root yield revealed significant difference in the environments, genotypes, and the interactions of both (P < 0.001). The genotypes NASPOT-12 was the mostly performed one over all the rest with total fresh storage root yield of 55.88 ton ha-1 while Kulfo was performed as the lowest. The AMMI1 and AMMI2 biplot analysis revealed that, the genotypes NASPOT-12 was resulted in an above average mean of total fresh storage root yield and the genotype Koka-12, NASPOT-13, NASPOT-12, and Kulfo were far apart from the biplot origin which indicated the genotypes were the more responsive and largely contributed to the interaction component and thus considered as specifically adapted genotypes respectively. The GGE biplot revealed that the total variations of 79% with the PC1 accounted about 55% and the PC2 affect about 24% of variations approximately on the total fresh storage root yield of the tested orange-fleshed sweet potato genotypes. The "which won where" identified the three growing mega environments. In the comparison and ranking of the genotypes by the GGE biplot analyses, the genotype NASPOT-12 was more desirable than the rest genotypes. In the comparison and ranking of the environments by this analysis, the environment Jimma-1 was the most representative followed by Agaro-2 in the total fresh storage root yield of orange-fleshed sweet potato genotypes. Above all the genotype NASPOT-12 was responded well in most of the environments hence, recommended genotype for multipurpose advantage.

Selection of High Yield and Stable Maize Hybrids in Mega-Environments of Java Island, Indonesia

Determination of grain yields of stable and high-yielding maize hybrids in a wide environment requires high accuracy. Many stability measurement methods have been used in multi-environment experiments. However, the relationships among the different methods are still difficult to understand. The objectives of this study were to 1. Identify the effect of growing season and location (Environments = E), hybrids (Genotypes = G), and their interactions (GEIs) on grain yields; 2. Select high-yielding and stable maize hybrids in a wide range of environments; 3. Determine the relationship between each stability estimation; and 4. Determine the mega-environment of maize hybrid and identify the best locations for testing. Field experiments were conducted at ten locations in Java Island, Indonesia, for two growing seasons using a randomized completed block design with three replications. The experimental results showed that the main effects of the growing season, location, hybrid, and GEIs, significantly affected maize hybrid yields. Stability estimations of TOP, S(3), S(6), NP(2), NP(3), KR, NP(4), CVi, and bi, belong to the concept of dynamic stability that can be used to select maize hybrids in favorable environments, while other estimations were classified as in the static stability. Three maize hybrids were successfully selected, with high and stable yields based on numerical and visual stability estimations, namely SC2, SC7, and SC9. The three hybrids can be used as candidates for sustainable maize development programs. The dry season, the rainy season, and the combination of two growing seasons produced three mega-environments. GJRS and KARS were the most discriminative environments. Both environments can be used as favorable environments for selecting the ideal maize hybrid.

Strong photosensitivity level doesn’t limit selection for high yield in winter bread wheat

Aim. The aim is to test the validity of home breeders assumption that strong photosensitivity in winter bread wheat limits the possibility of breeding improvement for productivity. Methods. Estimation of photosensitivity levels in modern high-yielding foreign cultivars (mainly from Western Europe) and in the set of F5 hybrids with photosensitivity diversity, which were selected only for relatively high yields. Results. Among the modern high-yielding foreign cultivars recommended for cultivation in Ukraine, carriers of strong photosensitivity have been identified with a significantly high frequency (up to 33.3 ± 0.75 %). In contrast, almost all modern Ukrainian cultivars are weakly photosensitive. When selecting in Odessa environment only the best-yielding families and lines from hybrid combinations, in which parents clearly differed in photosensitivity levels, F5 did not show a shift towards reducing the frequency of highly photosensitive phenotypes. It was statistically consistent with random variation without selection. Conclusions. High photosensitivity does not limit the efforts of breeders to improve the productivity potential of winter bread wheat. And for certain growing regions of this crop, it can be a factor in better environmental adaptability to get a real yield.

Selection for high yield and quality in half-diallel bread wheat F2 populations (Triticum aestivum L.) through heterosis and combining ability analysis

The study was carried out to evaluate the combining ability and heterosis of seven parents and their 21 half-diallel F2 populations for yield and quality traits during the 2013-14 season in the randomized complete block design with three replications. Significant differences were observed among the genotypes, GCA (general combining ability) and SCA (specific combining ability) effects for all traits, except spike length. The best combiner parents were identified as Esperia and Pehlivan for grain yield, and Flamura85, Aldane and Selimiye for quality traits because of significant GCA and per se performance. The ranges of best parent heterosis were -12.71 to 8.23% for plant height, -15.46 to 8.36% for spike length, -16.62 to 24.80% for number of grains per spike, -23.61 to 36.50% for grain weight per spike, -17.13 to 8.84% for harvest index and -44.26 to 15.83 for grain yield, -17.61 to 8.38% for thousand grain weight, -18.55 to 8.44% for wet gluten content, -33.80 to 24.78% for gluten index, -20.24 to 15.23% for Zeleny sedimentation value, -15.58 to 10.00% for quality index and -8.96 to 6.87 for grain protein content. The three (Slm/Phl, F85/Slm and F85/Esp) and seven (F85/Phl, Sb/Fs, Fs/Slm, Esp/Slm, Fs/Phl, Esp/Sb and Sb/Slm) of F2 populations are offered a good opportunity in base material for selection of potential because of significant SCA effects and best parent heterosis for grain yield and quality traits respectively.

Path analysis of phenotypic factors associated with grain protein in dryland winter wheat

ABSTRACT In hard red winter wheat (Triticum aestivum L.), increased understanding of relationships between grain protein concentration (GPC) and other phenotypic traits is needed for simultaneously achieving high yield and GPC through genetic improvement and management. Two field experiments with 20 genotypes each were conducted in 2018/2019 in Uvalde and Chillicothe, TX. The primary objective was to assess direct and indirect effects of phenotypic traits on GPC using path analysis. Broad-sense heritability was high for grain yield but low for GPC, indicating that breeding selection for high yield is best done directly, but selection for elevated GPC may be approached indirectly. Grains m−2 was positively related to GPC, though highly affected by environment, whereas 1000-kernel weight was negatively related to GPC and highly heritable. Heads m−2 had a negative direct influence on GPC, but a positive indirect effect of head number on GPC through grain number indicated head number would positively impact GPC if additional heads increased grain number. There were conflicting results between locations on the relationship between aboveground biomass at anthesis and GPC, similar to other reports. Increased time to physiological maturity positively affected GPC, with time to anthesis being the primary offsetting indirect factor, meaning a longer grain-filling period can likewise increase GPC. Crop management practices can interact with these phenotypic factors to affect GPC, which is discussed herein. These findings provide novel information on direct and indirect effects of several phenotypic traits on GPC, giving insights into routes for improvement of wheat quality through breeding and management.

Single-Plant Selection at Ultra-Low Density Enhances Buffering Capacity of Barley Varieties and Landraces to Unpredictable Environments and Improves Their Agronomic Performance.

Rainfall and temperature are unpredictable factors in Mediterranean environments that result in irregular environmental conditions for crop growth, thus being a critical source of uncertainty for farmers. This study applied divergent single-plant selection for high and low yield within five barley varieties and two Tunisian landraces under semi-arid conditions at an ultra-low density of 1.2 plants/m2 for two consecutive years. Progeny evaluation under dense stands following farmers’ practices was conducted in two semi-arid locations in Tunisia during one cropping season and in one location during a second season, totalling three environments. The results revealed significant genotypic effects for all recorded agronomic and physiological traits. No genotype × environment interaction was shown for biological yield, implying a biomass buffering capacity for selected lines under different environmental conditions. However, genotype × environment interaction was present in terms of grain yield since plasticity for biomass production under drought stress conditions was not translated directly to yield compensation for some of the lines. Nevertheless, several lines selected for high yield were identified to surpass their source material and best checks in each environment, while one line (IH4-4) outperformed consistently by 62.99% on average, in terms of grain yield, the best check across all environments. In addition, improved agronomic performance under drought conditions induced an indirect effect on some grain quality traits. Most of the lines selected for high yield maintained or even improved their grain protein content in comparison to their source material (average increase by 2.33%). On the other hand, most of the lines selected for low yield indicated a poor agronomic performance, further confirming the coherence between selection under ultra-low density and performance under dense stand.

Major Genomic Regions for Wheat Grain Weight as Revealed by QTL Linkage Mapping and Meta-Analysis.

Grain weight is a key determinant for grain yield potential in wheat, which is highly governed by a type of quantitative genetic basis. The identification of major quantitative trait locus (QTL) and functional genes are urgently required for molecular improvements in wheat grain yield. In this study, major genomic regions and putative candidate genes for thousand grain weight (TGW) were revealed by integrative approaches with QTL linkage mapping, meta-analysis and transcriptome evaluation. Forty-five TGW QTLs were detected using a set of recombinant inbred lines, explaining 1.76-12.87% of the phenotypic variation. Of these, ten stable QTLs were identified across more than four environments. Meta-QTL (MQTL) analysis were performed on 394 initial TGW QTLs available from previous studies and the present study, where 274 loci were finally refined into 67 MQTLs. The average confidence interval of these MQTLs was 3.73-fold less than that of initial QTLs. A total of 134 putative candidate genes were mined within MQTL regions by combined analysis of transcriptomic and omics data. Some key putative candidate genes similar to those reported early for grain development and grain weight formation were further discussed. This finding will provide a better understanding of the genetic determinants of TGW and will be useful for marker-assisted selection of high yield in wheat breeding.

Disparities among crop species in the evolution of growth rates: the role of distinct origins and domestication histories.

Growth rates vary widely among plants with different strategies. For crops, evolution under predictable and high-resource environments might favour rapid resource acquisition and growth, but whether this strategy has consistently evolved during domestication and improvement remains unclear. Here we report a comprehensive study of the evolution of growth rates based on comparisons among wild, landrace, and improved accessions of 19 herbaceous crops grown under common conditions. We also examined the underlying growth components and the influence of crop origin and history on growth evolution. Domestication and improvement did not affect growth consistently, that is growth rates increased or decreased or remained unchanged in different crops. Crops selected for fruits increased the physiological component of growth (net assimilation rate), whereas leaf and seed crops showed larger domestication effects on morphology (leaf mass ratio and specific leaf area). Moreover, climate and phylogeny contributed to explaining the effects of domestication and changes in growth. Crop-specific responses to domestication and improvement suggest that selection for high yield has not consistently changed growth rates. The trade-offs between morpho-physiological traits and the distinct origins and histories of crops accounted for the variability in growth changes. These findings have far-reaching implications for our understanding of crop performance and adaptation.

Drought and crop yield.

Episodes of water shortage occur in most agricultural regions of the world. Their durations and intensities increase, and their seasonal timing alters with changing climate. During the ontogenic cycle of crop plants, each development stage, such as seed germination, seedling establishment, vegetative root and shoot growth, flowering, pollination and seed and fruit development, is specifically sensitive to dehydration. Desiccation threatens yield and leads to specific patterns, depending on the type of crop plant and the harvested plant parts, e.g. leafy vegetables, tubers, tap roots or fruits. This review summarizes the effects of drought stress on crop plants and relates the dehydration-dependent yield penalty to the harvested organ and tissue. The control of shoot transpiration and the reorganization of root architecture are of core importance for maintaining proper plant water relationships. Upon dehydration, the provision and partitioning of assimilates and the uptake and distribution of nutrients define remaining growth activity. Domestication of crops by selection for high yield under high input has restricted the genetic repertoire for achieving drought stress tolerance. Introgression of suitable alleles from wild relatives into commercial cultivars might improve the ability to grow with less water. Future research activities should focus more on field studies in order to generate more realistic improvements to crops. Robotic field phenotyping should be integrated into genetic mapping for the identification of relevant traits.

Cassava genotypes selection for high yield and high starch content in advanced yield trials

Increasing the cassava-based industry requires a large and continuous supply of tubers. Tuber production is increased with planting high yielding varieties with high starch content. This study aimed to select cassava genotypes obtained from open pollination among parents showing high yield and starch content in the advanced yield trial (AYT) stage. The experiment was carried out at Muneng research station (Probolinggo District, East Java, Indonesia) using randomized complete block design with three replications and two planting seasons (2018 and 2019). The experiments used 24 cassava genotypes, including three varieties as a control (Adira 4, UJ 5, and Litbang UK 2). The cassava planted in 2018 was exposed to stress due to drought, while in 2019, the plants received optimal water availability. During the drought stress, the attack of red mite (Tetranycus sp) negatively correlated with tuber yield. In optimal water conditions, the symptoms of red mite attack are low. Based on the combined analysis of variance, genotype × growing season interaction affected plant height at six months, and at ten months for tuber yield, starch content, and starch yield. Among the clones tested, OMM 1207-22 produced the highest tubers yield with an average of 47.5 t·ha-1 in the two growing seasons, with the starch yield, was equivalent to 8.89 t·ha-1, significantly higher compared with the Litbang UK 2 variety (average tubers yield 41.5 t·ha-1, starch yield 7.40 t·ha-1,). Also, 13 genotypes produced starch ranging from 6.49 t·ha-1 to 8.33 t·ha-1.

Major genomic regions responsible for wheat yield and its components as revealed by meta-QTL and genotype-phenotype association analyses.

Meta-QTL (MQTL) analysis was done for yield-related traits in wheat. Candidate genes were identified within the refined MQTL and further validated by genotype-phenotype association analysis. Extensive studies have been undertaken on quantitative trait locus/loci (QTL) for wheat yield and its component traits. This study conducted a meta-analysis of 381 QTL related to wheat yield under various environments, including irrigated, drought- and/or heat-stressed conditions. Markers flanking meta-QTL (MQTL) were mapped on the wheat reference genome for their physical positions. Putative candidate genes were examined for MQTL with a physical interval of less than 20Mbp. A total of 86 MQTL were identified as responsible for yield, of which 34 were for irrigated environments, 39 for drought-stressed environments, 36 for heat-stressed environments, and 23 for both drought- and heat-stressed environments. The high-confidence genes within the physical positions of the MQTL flanking markers were screened in the reference genome RefSeq V1.0, which identified 210 putative candidate genes. The phenotypic data for 14 contrasting genotypes with either high or low yield performance-according to the Australian National Variety Trials-were associated with their genotypic data obtained through ddRAD sequencing, which validated 18 genes or gene clusters associated with MQTL that had important roles for wheat yield. The detected and refined MQTL and candidate genes will be useful for marker-assisted selection of high yield in wheat breeding.

The MYB transcription factor TaPHR3-A1 is involved in phosphate signaling and governs yield-related traits in bread wheat.

Improved inorganic phosphate (Pi) use efficiency in crops will be important for sustainable agriculture. Exploring molecular mechanisms that regulate Pi uptake could provide useful information for breeding wheat with improved Pi use efficiency. Here, a TaPHR3-A1 (Gene ID: TraesCS7A02G415800) ortholog of rice OsPHR3 that functions in transcriptional regulation of Pi signaling was cloned from wheat chromosome 7A. Ectopic expression of TaPHR3-A1 in Arabidopsis and rice produced enhanced vegetative growth and more seeds. Overexpression in transgenic rice led to increased biomass, grain number, and primary panicle branching by 61.23, 42.12, and 36.34% compared with the wild type. Transgenic wheat lines with down-regulation of TaPHR3-A1 exhibited retarded growth and root hair development at the seedling stage, and showed yield-related effects at the adult stage when grown in both low- and sufficient Pi conditions, indicating that TaPHR3-A1 positively regulated tolerance to low Pi. Introgression lines further confirmed the effect of TaPHR3-A1 in improving grain number. The Chinese wheat mini core collection and a recombinant inbred line analysis demonstrated that the favorable allele TaPHR3-A1-A associated with higher grain number was positively selected in breeding. A TaPHR3-A1-derived cleaved amplified polymorphic sequence marker effectively identified haplotype TaPHR3-A1-A. Our results suggested that TaPHR3-A1 was a functional regulatory factor for Pi uptake and provided useful information for marker-assisted selection for high yield in wheat.

Correlation and path analysis in tomato (Solanum lycopersicum L.) for yield and yield contributing traits

The evaluation of sixteen genotypes of tomato (Solanum lycopersicum L.) were carried out at Vegetable Research Farm of Department of Horticulture, Institute of Agricultural Sciences, B.H.U., Varanasi-221 005, Uttar Pradesh during Rabi season of 2016- 2017. Genotypic correlations were comparatively higher than the respective phenotypic correlations for most of the traits. Average fruit weight, fruit width, fruit length, number of locules per fruit and number of seeds per fruit showed significant positive correlation with yield (q/ha) indicating that selection for higher yield through these traits would be effective. Path coefficient analysis indicated highest positive direct effect towards yield via. days to 50% flowering followed by fruit width, total soluble solids and average fruit weight. These traits may be given more emphasis for direct selection of high yielding tomato genotypes in future breeding programmes.

The coordinated increase in stomatal density and vein dimensions during genetic improvement in rice

AbstractRice (Oryza sativa L. ssp. indica) has experienced three distinct phases of considerable yield increases: Green Revolution, utilization of heterosis, and the combination of ideotype and inter‐subspecific hybrid breeding. Crop breeding and selection for high yield have increased radiation use efficiency in modern indica rice varieties. However, the underlying leaf morphological and physiological changes have not been established. Field and pot experiments were conducted in 2016 and 2017. We investigated the relationships between the anatomical maximum stomatal conductance (gmax), operational stomatal conductance (gop), and the anatomy of the stomata and vein in relation to leaf‐level transpiration and photosynthesis across historical indica rice varieties. The results showed that flag leaf temperature of new varieties was reduced relative to the temperature of older varieties due to increased gop and leaf transpirational cooling. Both high stomatal density and larger veins were increased in new varieties with improved yield potential, while no change was observed in stomatal length and vein density. There was a significant correlation between stomatal density and gop as well as between gop and the light‐saturated photosynthetic rate. The present study reveals that historical selection for high yield is accompanied by leaf morphological changes that contribute to enhanced gop, leaf cooling, and photosynthesis of irrigated rice inhabiting hot, high light environments.

Use of NDVI for indirect selection of high yield in tropical rice breeding

Plant breeders evaluate large numbers of breeding lines/accessions and measure various traits in the field in order to identify and select elite genotypes with high yield. Therefore, information on highly correlated yield-related traits and simple high-throughput methods to predict grain yield would be useful for rice breeders. The objective of this study was to examine the usefulness of various traits as indirect selection criteria for high yield in tropical rice breeding, with an emphasis on rapid and non-destructive measurements. We evaluated a wide range of germplasm, including popular varieties, elite genotypes, and donor parents, in the irrigated rice breeding program at the International Rice Research Institute, in the Philippines, during the 2015 wet season and 2016 dry season. We measured the normalized-difference vegetation index (NDVI), leaf chlorophyll content (SPAD value), agronomic traits, and grain yield. Harvest index, NDVI at the heading and late grain-filling stages, and SPAD value at the late grain-filling stage were significantly correlated with yield during the wet season, whereas plant height, panicle length, and NDVI from panicle initiation to the booting stage during the dry season. Our results indicate that pre-harvest analysis of primary and secondary traits such as NDVI has potential for selecting high-yielding accessions in tropical rice breeding programs. By using low-cost portable equipment, NDVI measurements could be incorporated into breeding programs. Trait associations with yield differed between the dry and wet seasons, which has important implications for breeding new varieties and germplasm evaluation in different seasons.

English

Drought is the most important abiotic limitation to groundnut yields across the world, and the Northern Regions of Ghana. The study estimated the heritability and genetic variability of selected parents of groundnut for drought tolerance traits to aid in their effective selection and utilization. The North Carolina II mating design was adopted while the variance component method was used to estimate heritabilities in the narrow and broad sense as well. Chlorophyll content (greenness of leaves) was recorded at 60 and 80 DAP. The objective was to measure the chlorophyll content and hence the drought tolerance performance of the entries. Mean squares caused by differences among crosses was partitioned into difference due to male parents and female parents, which was attributed to general combining ability (GCA), as well as difference due to male x female interaction, which was attributed to specific combining ability (SCA). Narrow Sense Heritability from the variance components for different traits varied under both water regimes, ranging from 12.2% to 95.7%. The most heritable traits were: dry biomass weight (95.7%), days to 50% flowering (91.0%), seed yield (90.0%), plant height at harvest (76.0%), SCMR 60 DAP (71.7%), days to maturity (67.0%) and SCMR 80 DAP (66.0%). Pod yield (12.3%) and harvest index (12.2%) exhibited low narrow sense heritabilities. Additive gene effects largely controlled the inheritance of pod, seed and biomass yields. Positive association between most yield and yield components as well as higher heritabilities shows that selection for higher yield and maturity is conceivable in improving groundnuts. Key words: Abiotic, constraints, chlorophyll content, drought, genetic, groundnut, heritability, North Carolina II mating design, tolerance, yield.

Intense Breeding within Lentil Landraces for High-Yielding Pure Lines Sustained the Seed Quality Characteristics

Landraces are a valuable source of genetic variability for breeders to develop high-yielding lentil varieties. Apart from productivity, simultaneous breeding for lentil seed nutritional quality is of paramount importance for wider lentil consumption. This work examined the indirect effect of single plant selection for high yield on important seed quality traits within three Greek lentil landraces (“Elassona” (EL), “Lefkada” (L), and “Evros” (EV)). The breeding methodology applied was proved to help either maintain or improve such characteristics in the high-yielding second-cycle lines (SLs) selected. Compared to the parental landrace “Elassona”, the high-yielding lines showed increased crude fiber by 30–110%; the line 2-SL-EL-6 had higher starch content by 3.9% and reduced cooking time by 6.67 min, while the 2-SL-EL-10 line had higher crude fiber by 73%. In the case of “Lefkada”, the high-yielding lines selected maintained the protein content present in the parental landrace, apart from the 2-SL-L-1 where a decrease by 5% was recorded; however, most of them showed increased crude fiber (5.59–7.52%) in comparison with the parental landrace (4.65%). Finally, in relation to the “Evros” parental landrace, the 2-SL-EV-3 and 2-SL-EV-4 showed higher crude fiber and reduced cooking time. This study provides evidence that proper management of genetic variability could improve productivity without compromising or sometimes improving some seed quality traits.