Advanced Breeding Lines Research Articles

Screening of advanced rice breeding lines against Nilaparvata lugens (Stal.) resistance

Advanced rice breeding lines developed out of BPH resistant donars. These lines were derived by using R x R crossing pattern in breeding programme. Donars used were characterized with respect to agronomic traits viz., 100 seed weight value ranges between 1.95 to 4.13 g, total panicle per plant 4 to 17.4, total productive tillers between 5.2 to 10 and panicle length 18.1 to 143.7cm. Out of total accessions 114 rice advanced breeding lines were screened , out of these 15 were found highly resistant , 57 resistant, 12 moderately resistant and rest 30 lines susceptible.

Organic dry pea (Pisum sativum L.) biofortification for better human health.

A primary criticism of organic agriculture is its lower yield and nutritional quality compared to conventional systems. Nutritionally, dry pea (Pisum sativum L.) is a rich source of low digestible carbohydrates, protein, and micronutrients. This study aimed to evaluate dry pea cultivars and advanced breeding lines using on-farm field selections to inform the development of biofortified organic cultivars with increased yield and nutritional quality. A total of 44 dry pea entries were grown in two USDA-certified organic on-farm locations in South Carolina (SC), United States of America (USA) for two years. Seed yield and protein for dry pea ranged from 61 to 3833 kg ha-1 and 12.6 to 34.2 g/100 g, respectively, with low heritability estimates. Total prebiotic carbohydrate concentration ranged from 14.7 to 26.6 g/100 g. A 100-g serving of organic dry pea provides 73.5 to 133% of the recommended daily allowance (%RDA) of prebiotic carbohydrates. Heritability estimates for individual prebiotic carbohydrates ranged from 0.27 to 0.82. Organic dry peas are rich in minerals [iron (Fe): 1.9-26.2 mg/100 g; zinc (Zn): 1.1-7.5 mg/100 g] and have low to moderate concentrations of phytic acid (PA:18.8-516 mg/100 g). The significant cultivar, location, and year effects were evident for grain yield, thousand seed weight (1000-seed weight), and protein, but results for other nutritional traits varied with genotype, environment, and interactions. "AAC Carver," "Jetset," and "Mystique" were the best-adapted cultivars with high yield, and "CDC Striker," "Fiddle," and "Hampton" had the highest protein concentration. These cultivars are the best performing cultivars that should be incorporated into organic dry pea breeding programs to develop cultivars suitable for organic production. In conclusion, organic dry pea has potential as a winter cash crop in southern climates. Still, it will require selecting diverse genetic material and location sourcing to develop improved cultivars with a higher yield, disease resistance, and nutritional quality.

Study of diversity in thermo-tolerant advanced lines of Wheat (Triticum aestivum L.) for Morpho-physiological, Yield and its Contributing Traits

The present study was carried out to examine the genetic diversity among 151 thermo-tolerant advanced breeding lines of wheat for two experimental years during Rabi 2017-18 and Rabi 2018-19 in randomized block design in an area of 312 m2 at Field Experimentation Center, Department of Genetics and Plant Breeding, SHUATS, Allahabad. The data were recorded in both the seasons for total 23 traits i.e. 18 quantitative characters to study variability, heritability, genetic advance and genetic divergence and 5 morphological characters. ANOVA showed significant differences for all the characters except flag leaf width, in both experimental seasons and for gluten content in season Rabi 2018-19 indicating the presence of a substantial amount of genetic variability which thus revealed different genetic backgrounds of genotypes. High estimates of both GCV and PCV were observed for biological yield in both experimental years. High heritability with high genetic advance was recorded for all quantitative characters except flag leaf width and gluten content indicating the predominance of additive gene effects and hence the possibilities of effective selection for the improvement of these traits. D2 analysis grouped these lines into 10 clusters in which cluster VII was biggest cluster with 26 lines. Further diversity analysis revealed that cluster IV and VII followed by Cluster VI and Cluster VII were most divergent from each other, and the genotypes present in them may be used as parents for further hybridization program to develop desirable heat type in wheat. Analysis of 5 Morphological characters i.e. leaf type, rachis colour, leaf shape, waxiness and stay green habit, depicted that HUW-213 x NW-1076 followed by HALNA x RAJ-4037 were found above average yielders and terminal heat tolerant primarily due to their semi-erect leaf type, green rachis color, broad leaf shape, stay green habit and less days to maturity as compared to checks.

Association analysis and evaluation of sources for resistance to phyllody and foliar diseases in sesame (Sesamum indicum L.)

In the present investigation, a set of advanced mutant and breeding lines (133) including checks from different geographical regions were evaluated against phyllody and Alternaria leaf spot during kharif, 2017 and against powdery mildew during summer, 2018 under natural epiphytotic field conditions. Among the entries, two genotypes (LW-2 and SDSN-15-98) were found to be promising for phyllody during kharif, 2017 whereas, the genotype LW-2 was also found to be moderately resistant against powdery mildew during summer, 2018. None of the genotypes were promising against Alternaria leaf spot. The association of agronomic traits namely plant height, thousand seed weight, number of branches/plant, number of capsules/ plant was correlated negatively significant with diseases. The genotype LW-2 identified promising against phyllody and powdery mildew will be useful in hybridization programme as donor parent for development of multiple disease resistant sesame varieties.

Improvement of genomic prediction in advanced wheat breeding lines by including additive-by-additive epistasis

Key messageIncluding additive and additive-by-additive epistasis in a NOIA parametrization did not yield orthogonal partitioning of genetic variances, nevertheless, it improved predictive ability in a leave-one-out cross-validation for wheat grain yield.Additive-by-additive epistasis is the principal non-additive genetic effect in inbred wheat lines and is potentially useful for developing cultivars based on total genetic merit; nevertheless, its practical benefits have been highly debated. In this article, we aimed to (i) evaluate the performance of models including additive and additive-by-additive epistatic effects for variance components (VC) estimation of grain yield in a wheat-breeding population, and (ii) to investigate whether including additive-by-additive epistasis in genomic prediction enhance wheat grain yield predictive ability (PA). In total, 2060 sixth-generation (F6) lines from Nordic Seed A/S breeding company were phenotyped in 21 year-location combinations in Denmark, and genotyped using a 15 K-Illumina-BeadChip. Three models were used to estimate VC and heritability at plot level: (i) “I-model” (baseline), (ii) “I + GA-model”, extending I-model with an additive genomic effect, and (iii) “I + GA + GAA-model”, extending I + GA-model with an additive-by-additive genomic effects. The I + GA-model and I + GA + GAA-model were based on the Natural and Orthogonal Interactions Approach (NOIA) parametrization. The I + GA + GAA-model failed to achieve orthogonal partition of genetic variances, as revealed by a change in estimated additive variance of I + GA-model when epistasis was included in the I + GA + GAA-model. The PA was studied using leave-one-line-out and leave-one-breeding-cycle-out cross-validations. The I + GA + GAA-model increased PA significantly (16.5%) compared to the I + GA-model in leave-one-line-out cross-validation. However, the improvement due to including epistasis was not observed in leave-one-breeding-cycle-out cross-validation. We conclude that epistatic models can be useful to enhance predictions of total genetic merit. However, even though we used the NOIA parameterization, the variance partition into orthogonal genetic effects was not possible.

Caninde2/Milan: promising wheat line to discover novel genes for resistance to wheat blast

Wheat blast disease is responsible for severe production losses. The disease resistance associated with the 2NS/2AS translocation is effective, but its level can be variable. In this study, we evaluated the presence of 2NS/2AS translocation in 310 advanced breeding lines from six crosses (Caninde 2/Milan, Milan/Caninde 2, Maringa/Milan, Milan/Maringa, Ciano79/Milan and Milan/Ciano79), and also studied their wheat blast reaction in the field to three virulent pathogen strains (P13-009, P14-031 and P14-039) collected in Paraguay. Advanced lines of two crosses (Caninde 2/Milan and Milan/Caninde 2) yielded the highest number of blast-resistant entries without 2NS/2AS translocation. Earlier studies have shown Caninde 2 to be a moderately susceptible line, which in combination with Milan, is probably adding non-2NS/2AS type resistance to these crosses. Our result indicates that such a resistance is based on several additive factors derived from multiple sources, which need to be explored further and also used to develop more durable wheat blast-resistant germplasm in the future.

Importance of Participatory Variety Selection and Participatory Plant Breeding in Variety Development and Adoption

Participatory varietal selection and participatory plant breeding are two new terminologies that include both old and new concepts and procedures. The degree and timing of farmer involvement in plant breeding determines the difference between participatory varietal selection and participatory plant breeding. The main difference between participatory plant breeding and participatory varietal selection is the degree of farmer involvement in the various stages of the breeding program. Participatory varietal selection involves farmers testing and selecting new varieties generated by the institutional system in their fields and at local research stations in a range of environments, as well as comparing these varieties to local farmer varieties while in a participatory plant breeding, farmers are often involved in decision-making throughout the breeding process, not just in the final testing of advanced breeding lines. Farmers are the primary beneficiaries of a participatory variety selection program because they are the end-users of agricultural technologies. The participatory variety selection method provides researchers valuable feedback that allows them to focus their research program to properly meet the demands of farmers. The poorest farmers should to profit from new varieties by promoting collaboration between plant breeders and farmers. However, poor farmers in marginal areas continue to produce obsolete crop varieties that are low yielding, susceptible to pests and disease and are less fitted to farmers' actual challenges and opportunities. These farmers have little exposure to new varieties, and those that have been released are frequently unsuitable for marginal areas. Therefore, participatory variety selection is very critical to introducing improved crop varieties to new growing environments based on farmers preferred traits and selected improved crop varieties. In order to enhance improved crop varieties, farmers' preferences must be taken into account across regions and growing seasons that farmers will accept. Generally, participatory varietal selection and participatory plant breeding are the way to overcome the issue of local adaptation and demand driven improved technologies. Participatory Varietal Selection and client-oriented breeding are two methods used to achieve farmers’ profitability with improved crop varieties.

Character Association and Path Coefficient Analysis in Indian Mustard (Brassica juncea L.)

Background: Correlation analysis informs us about the relative importance of the breeding traits and quite useful for plant breeders to formulate their breeding and selection strategies. Path coefficient analysis splits the correlation coefficient into the measures of indirect and direct effect. It identifies the indirect and direct influence of different autonomous genotype on a dependent trait. Present study aimed to determine major seed contributing components affecting seed yield and also to know the relationship among these components. Methods: Present investigation was carried out on 147 advanced breeding lines to know the correlations and path coefficient for 12 yield and yield contributing traits. The material was evaluated in augmented block design with 07 blocks, each block having 21 lines. A set of three check varieties were repeated in each block. Observations were recorded on number of primary branches/plant, number of secondary branches/plant, plant height (cm), silique/plant, fruiting zone length (cm), main shoot length (cm), number of seeds/siliquae, siliquae length (cm), biological yield/plant (g), seed yield/plant (g), harvest index and test weight. Result: The seed yield per plant showed positive and significant correlation with primary branches per plant (0.273), secondary branches per plant (0.280), siliquae per plant (0.627), biological yield per plant (0.744), harvest index (0.188), test weight (0.212) and oil content (0.225). Biological yield per plant (0.5747) had maximum direct effect on seed yield per plant followed by siliquae per plant (0.2438), harvest index (0.127), oil content (0.118) and test weight. These characters have positive and significant association with seed yield per plant. The study thus indicated that biological yield per plant, siliquae per plant, harvest index and test weight are the important characters which should be considered in selection programme in Indian mustard.

Development of Drought Tolerant Rice Breeding Lines of an Elite Indian Rice (Oryza sativa L.) Variety Improved White Ponni through Molecular Breeding

Changes in climatic conditions especially unpredictable drought occurrences are challenging for food security. The present investigation was carried out to improve the grain yield in Improved White Ponni (IWP) rice under reproductive stage drought stress. This variety is well known for its grain quality. Physiological changes, grain yield and related traits under drought were evaluated in the advanced breeding lines of Improved White Ponni X Apo containing qDTY 3.1. The experiment was conducted at the Department of Rice, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural university, Coimbatore during 2020. Two superior backcross inbred lines of IWP X Apo, donor parent and recipient parent were raised under water stress in rain out shelter as well as in well irrigated conditions in replications. Soil moisture content was reduced to 12.7% in drought field showing the stress severity. Physiological parameters such as photosynthetic rate, transpiration rate, stomatal conductance, chlorophyll content and relative water content, Yield and related traits such as days to fifty percent flowering, productive tillers, spikelet fertility, grain yield and grain weight were recorded in the BILs and parents during flowering stages. Reduction was observed in all these traits under water stress. However, in comparison with IWP (94.6%) which lacks qDTY 3.1, BILs with qDTY 3.1 showed less reduction in grain yield (63%) and other traits. Earliness was also observed in qDTY 3.1 containing BILs under drought stress (BILs - 106 days, IWP-117 days) and controlled conditions (BILs- 83 days, IWP-107 days) when compared to IWP. Grain quality estimates in the BILs showed similarity to IWP. These BILs need to be evaluated further for confirmation of drought tolerance and they are effective resources for utilisation in drought breeding programmes.

Exploring the Relationship between Yield and Yield Attributing Traits in Advanced Breeding Lines of Rice (Oryza sativa L.)

Aim: Present study endeavors to explore the genetic variability for various agro-morphological and quality traits as well as to delineate the association between grain yield and its yield attributing components
 Study Design: Randomized Complete Block Design
 Place and Duration of Study: Division of Plant Breeding and Genetics, She-e-Kashmir University of Agricultural Sciences and Technology of Jammu during kharif 2020.
 Methodology: A experiment was carried out to determine the association between grain yield and yield attributing components among advanced breeding lines of rice to establish a well grounded selection criteria for developing rice varieties with improved grain yield. Phenotypic coefficient of variation (PCV) was found to be relatively greater than the genotypic coefficient of variation (GCV) for most of traits indicating role of environment in the phenotypic expression of traits. Characters viz., plant height, total number of tillers per plant, number of effective tillers per plant, panicle length and grain yield per plant exhibited high heritability coupled with high genetic advance indicating their efficient inheritance from preceding generations.
 Results: Association studies indicated that characters viz., Plant height, total number of tillers per plant, number of effective tillers per plant, panicle length, 1000 grain weight and grain yield per plant had a significant positive relationship with grain yield per plot indicating their role in breeding rice varieties for higher grain yield.
 Conclusion: Cause and effect relationship revealed that traits viz., days to 50 per cent flowering, total number of tillers per plant, days to maturity, panicle length and grain yield per plant can be exploited for indirect selection for improving grain yield.

Phenotypic Evaluation of Advanced Breeding Lines for Resistance against Bacterial Leaf Blight Disease in Rice (Oryza sativa L.)

Bacterial Leaf Blight disease epidemically damaged the rice crop. Absence of resistance against BLB disease in MTU1010 is one of the main reason for these epidemics. Thus, there is urgent need to search for resistant source and subsequently, their phenotypic evaluation to validate the resistant source. In this paper discussing about the highlights of phenotypic evaluation of Bacterial Leaf Blight resistance in MTU1010 NIL variety of rice. In the present study, fifty advanced breeding lines along with parents i.e., MTU1010 NIL X Akshayadhan NIL, were screened for bacterial leaf blight disease, Thirty-four breeding lines were shown resistance against bacterial leaf blight disease.

Screening and Validation of Drought Tolerance and Fusarium Wilt Resistance in Advance Breeding Lines of Chickpea (Cicer arietinum L.)

Background: Approximately 90% of the world’s chickpea is grown under rainfed conditions where terminal drought is one of the major constraints limiting productivity. The need of short-duration, Fusarium wilt tolerant cultivars/elite lines and able to escape drought due to early maturity were required. Methods: The present investigation was carried out using 54 genotypes, generated from six diverse crosses, along with ten checks (resistant/tolerance, susceptible) were screened against drought and Fusarium wilt at Zonal Agricultural Research Station, Kalaburagi, Karnataka (Latitude: 17.36 and Longitude: 76.82) during crop season 2018-19. Result: The results revealed that higher PCV, GCV, heritability, percent genetic advance were exhibited by number of pods per plant and seed yield per plot, whereas lower PCV, GCV recorded for days to 50% flowering and days to maturity in both normal and late sown conditions. The advanced breeding lines viz., KCD-8, KCD-24, KCD-28, KCD-32, KCD-37 and KCD-53 were identified as drought tolerant lines based on drought tolerant indices (viz., MP, YSI, DTE and DSI). The lines KCD-48 and KCD-32 were identified as Fusarium wilt resistance with lowest PDI of 1.47 and 2.46 respectively, as they were screened in wilt sick plot and further these were validated and confirmed the resistant alleles using two unpublished SNP markers (FW2_30366110 and FW2_30365816). The advanced breeding lines KCD-32 and KCD-37 were identified as drought tolerant and Fusarium wilt resistant.

Phenotypic and molecular screening of dry bean (Phaseolus vulgaris L.) breeding lines for resistance to bean common mosaic virus and bean common mosaic necrosis virus

Bean common mosaic virus (BCMV) and bean common mosaic necrosis virus (BCMNV) are among the most economically important virus species infecting common bean. The use of resistant plant cultivars is the most effective way to control these viruses. National dry bean breeding studies have been conducted by seven different governmental agricultural research institutes in Turkey, and advanced breeding lines have been developed by using the selected local dry bean populations and crossing studies. In this study, 204 breeding lines were tested for resistance levels to BCMV and BCMNV. Initially, BCMNV NL-3 and BCMV NL-4 strains were individually sap-inoculated onto the leaves of bean plants belonging to each breeding lines with 10 replications, and the reactions of plants were evaluated for symptomatic appearance of virus infection 21 days after inoculation. Additionally, phenotypic evaluation was confirmed by molecular markers linked to resistance genes. As a result of the study, 153 breeding lines were found to involve the dominant I gene whereas four and five of the tested lines had the recessive genes bc-1² and bc-2², respectively. In conclusion, it was emphasized that these breeding lines could be registered after evaluating them in terms of yield and quality. Also, the use of seeds of the resistant lines to supply the source of virus-resistance in breeding studies and maintaining their seeds at the national genebank were recommended.

Identification of Resistant Germplasm and Detection of Genes for Resistance to Powdery Mildew and Leaf Rust from 2,978 Wheat Accessions.

Powdery mildew and leaf rust, caused by Blumeria graminis f. sp. tritici and Puccinia triticina, respectively, are widespread diseases of wheat worldwide. The use of resistant cultivars is considered the most economical, environment-friendly, and effective method to control these diseases. In the present study, a collection of 2,978 wheat accessions consisting of 1,394 advanced breeding lines, 1,078 Chinese cultivars, 291 introduced cultivars, 132 lines containing alien chromosomes, and 83 landraces was tested for reactions to powdery mildew and leaf rust. The results indicated that 659 wheat accessions (22.1%) were highly resistant to a widely prevalent B. graminis f. sp. tritici isolate, E09, at the seedling stage, and 390 were consistently resistant to the mixture of B. graminis f. sp. tritici isolates at the adult plant stage. Meanwhile, 63 accessions (2.1%) were highly resistant to leaf rust at the adult plant stage, of which 54 were resistant to a predominant and highly virulent P. triticina race, THTT, at the seedling stage. Notably, 17 accessions were resistant to both powdery mildew and leaf rust. To detect known genes for resistance to powdery mildew and leaf rust, these accessions were tested with gene-specific or tightly linked markers for seven powdery mildew genes (Pm genes; Pm2, Pm4, Pm5, Pm6, Pm8, Pm21, and Pm24) and 10 Lr genes (Lr1, Lr9, Lr10, Lr19, Lr20, Lr24, Lr26, Lr34, Lr37, and Lr46). Of the 659 powdery mildew-resistant accessions, 328 might carry single Pm genes and 191 carry combined Pm genes. Pm2 was detected at the highest frequency of 59.6%, followed by Pm8, Pm6, Pm21, Pm4, and Pm5, whereas Pm24 was not detected. In addition, 139 accessions might contain unknown Pm genes different from those tested in this study. In the 63 accessions resistant to leaf rust, four leaf rust genes (Lr genes; Lr1, Lr10, Lr26, and Lr34) were detected in 41 accessions singly or in combination, whereas six genes (Lr9, Lr19, Lr20, Lr24, Lr37, and Lr46) were not detected. Twenty-two accessions might contain unknown Lr genes different from those tested in this study. This study not only provided important information for rationally distributing resistance genes in wheat breeding programs, but also identified resistant germplasm that might have novel genes to enrich the diversity of resistance sources.

Phenotyping and Association Analysis of Zinc Biofortified Rice Varieties for Grain Yield and Quality Traits

A set of 25 test genotypes including 11 promising high zinc landraces, four zinc biofortified released varieties, six Zn-dense advance breeding lines, one OUAT rice variety, one zinc dense check variety “Chittimatyalu” and three low zinc mega varieties of rice (Swarna and Sambamahsuri) were assessed for grain Zn content and inter-relationship among seed yield and quality traits. P44 selection revealed highest Zn content (52.7ppm) followed by Basudha, Manika, Nikipankhia, ORCZ 75-3-1 and Tikimashuri with Zn content more than 40 ppm. Grain yield showed a significant positive correlation with a number of ear-bearing tillers m-2 and grain number panicle-1. Plant height exhibited a negative correlation with a number of effective bearing tillers m-2 and seed yield, but positively correlated with zinc content which seems to be the major hindrance for breeding semi-dwarf high yielding Zn-dense. The tall indica landraces such as Malliphulajhulli (43.8 ppm), Nikipankhia (42.8 ppm), Padmavati (31.3 ppm), Tikimahsuri (41.5 ppm), and Basudha (44.4 ppm) harbor high grain zinc content but revealed low yield potential. Transfer of zinc transporter genes available in the above tall indica types to semi-dwarf plant types may enrich the status of zinc content in grain.

Profiling carotenoid and sugar contents in unique Cucumis melo L. cultigens harvested from different climatic regions of the United States

The sensory and functional quality attributes of muskmelons (Cucumis melo L.), such as flavor, sweetness, color, and texture, determine consumer preferences. Genetic makeup primarily regulates these traits, but environmental factors such as soil type, irrigation, and temperature affects yields and quality. Here, we investigated variation in quality traits of diverse melon cultigens (advanced breeding lines or cultigen) grown in multiple locations (California, Texas, Georgia, Arizona, and North Carolina) across the United States. Mesocarp sugar and carotenoid concentrations varied significantly as a function of production location and cultigen. Multivariate analyses revealed significant cultigen, location, and interactive effects on fruit quality. The highest sugar content was found in a honeydew melon cultigen (HD-150; 83.1 ± 2.36 mg/g) grown in Georgia and the Western Shipper type cantaloupe (F-39; 70.8 ± 2.85 mg/g) grown in North Carolina compared to the other cultigens. The Tuscan type (Da Vinci) grown in Texas and Georgia had the highest β-carotene contents (29.1 ± 3.37 and 33.6 ± 1.73 μg/g, respectively) compared to the other cultigens. These findings suggest that cultivar and location significantly influenced melon phytochemical composition, will help melon breeding programs improve the sensory and functional qualities of melons and identify suitable cultivars for specific environments to maximize fruit quality.

Breeding for higher yield, early maturity, wider adaptability and waterlogging tolerance in soybean (Glycine max L.): A case study

Breeding for higher yield and wider adaptability are major objectives of soybean crop improvement. In the present study, 68 advanced breeding lines along with seven best checks were evaluated for yield and attributing traits by following group balanced block design. Three blocks were constituted based on the maturity duration of the breeding lines. High genetic variability for the twelve quantitative traits was found within and across the three blocks. Several genotypes were found to outperform check varieties for yield and attributing traits. During the same crop season, one of the promising entries, NRC 128,was evaluated across seven locations for its wider adaptability and it has shown stable performance in Northern plain Zone with > 20% higher yield superiority over best check PS 1347. However, it produced 9.8% yield superiority over best check in Eastern Zone. Screening for waterlogging tolerance under artificial conditions revealed that NRC 128 was on par with the tolerant variety JS 97–52. Based on the yield superiority, wider adaptability and waterlogging tolerance, NRC 128 was released and notified by Central Varietal Release Committee (CVRC) of India, for its cultivation across Eastern and Northern Plain Zones of India.

Genomic prediction of preliminary yield trials in chickpea: Effect of functional annotation of SNPs and environment.

Achieving yield potential in chickpea (Cicer arietinum L.) is limited by many constraints that include biotic and abiotic stresses. Combining next-generation sequencing technology with advanced statistical modeling has the potential to increase genetic gain efficiently. Whole genome resequencing data was obtained from 315 advanced chickpea breeding lines from the Australian chickpea breeding program resulting in more than 298,000 single nucleotide polymorphisms (SNPs) discovered. Analysis of population structure revealed a distinct group of breeding lines with many alleles that are absent from recently released Australian cultivars. Genome-wide association studies (GWAS) using these Australian breeding lines identified 20 SNPs significantly associated with grain yield in multiple field environments. A reduced level of nucleotide diversity and extended linkage disequilibrium suggested that some regions in these chickpea genomes may have been through selective breeding for yield or other traits. A large introgression segment that introduced from C. echinospermum for phytophthora root rot resistance was identified on chromosome 6, yet it also has unintended consequences of reducing yield due to linkage drag. We further investigated the effect of genotype by environment interaction on genomic prediction of yield. We found that the training set had better prediction accuracy when phenotyped under conditions relevant to the targeted environments. We also investigated the effect of SNP functional annotation on prediction accuracy using different subsets of SNPs based on their genomic locations: regulatory regions, exome, and alternative splice sites. Compared with the whole SNP dataset, a subset of SNPs did not significantly decrease prediction accuracy for grain yield despite consisting of a smaller number of SNPs.

Unravelling genetic variability for moisture stress tolerance in Indian mustard and identification of high breeding value donor lines

Aim: Identification of high breeding value donor lines harbouring tolerance to moisture stress from diversity stock of 443 genotypes of Brassica juncea. Methodology: Germplasm stock of 443 Indian mustard (Brassica juncea L.) genotypes, comprising introgression lines, land races, old cultivars and advance breeding lines, were evaluated under two environments viz., irrigated and rainfed conditions to check the variability for yield and related traits. Statistical software META-Rver 6.0 (Multi Environment Trial Analysis using R) was used for computation of Best Linear Unbiased Predictions, Analysis of Variance (ANOVA), Genetic Correlations and Heritability. Drought susceptibility index and per cent seed yield reduction under rainfed conditions were used as indicators to determine moisture stress tolerance in genotypes. Results: The variability for moisture stress tolerance has been unravelled in a diverse genetic stock of Brassica juncea under two environments: irrigated and rainfed. For high prediction accuracy, the ranking of genotypes was done based on Best Linear Unbiased Predictions for seed yield and its component traits. PBR-378, RGN-329, RB-73, RB-50 and PBR-422 and Giriraj were identified as moisture stress tolerant genotypes. One land race Sahib 36 and three introgression lines viz., MCP 12-211, PTJ-3-69 and MSC-3 have also been identified as potential genetic resources for moisture stress tolerance. Principal component analysis based on biplots depicted specific distribution of variables for each environment. Interpretation: This study led to the identification of potential donors for moisture stress tolerance with high predictive accuracy. Low drought susceptibility index and high breeding value in a land race and three introgression lines derived from Erucastrum cardaminoides, B. tournefortii and B. carinata emphasized their utilization as potential genetic resources to breed for moisture stress tolerance in B. juncea.

Multienvironment evaluation of St. Augustinegrass breeding lines for turf performance via a mixed‐models approach

AbstractSt. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] is a turfgrass extensively used in managed landscapes in Florida and throughout the southeastern United States. To develop cultivars with broad adaptation, it is necessary to understand the effect of genotype × environment interactions. The objective of this study was to estimate genetic parameters in St. Augustinegrass for coverage, turf quality (TQ), and turf color (TC) in a multienvironment trial across five locations in Florida (Arcadia, Hague, Citra, Cocoa Beach, and Jay) evaluated over 5 yr (2011–2016). The experiment consisted of 26 advanced breeding lines, and four cultivars: ‘Floraverde’, ‘SS‐100’ (Palmetto®), ‘NUF‐76’ (Captiva®), and ‘Floratam’. Trials were arranged as randomized complete block designs with three replications. Linear mixed models with repeated measures were implemented in ASReml‐R. Significant differences were observed among genotypes. The estimates of genotype‐mean broad‐sense heritabilities ranged from 0.37 to 0.96 for coverage, 0.00 to 0.37 for TC, and 0.27 to 0.93 for TQ. Genotypic correlations ranged from 0.05 to 0.90 for coverage, 0.48 to 0.69 for TC, and 0.35 to 0.83 for TQ, indicating stable genotypic performance for TQ and TC between locations. For coverage, most genotypes clustered together, whereas greater genotypic variability was observed for TQ and TC. Genotypes ‘04‐4‐1‐4‐6’ and ‘FSA1602’ showed the best overall performance across the different traits analyzed for most locations and both genotypes are recommended for further use in future crosses in the breeding program. FSA1602 was recently released as FSA1602 and is being commercialized under the trademark CitraBlue®.