Early selection of soybean yield via agronomic trait phenotyping under Asian soybean rust pressure

The Asian soybean rust (Phakopsora pachyrhizi H. Sydow & P. Sydowj, which has been reported in areas of tropical and subtropical climates around the world, causes significant soybean (Glycine max L. Merr.) yield reduction. The disease progress is influenced by biotic factors such as interaction pathogen/host and abiotic factors of the environment. This work presents three models using bayesian approach to study Asian Suprema soybean rust incidence in different temperature and leaf wetness conditions. The models present estimates equivalents to non-linear regression model of Reis et al, fuzzy model of Alves et al and neuro-fuzzy model of Silva et al, when compared on the results from experimental design realized by Alves et al.

Plant lodging is a problem in soybean [Glycine max (L.) Merr.] production, particularly in high‐yield environments. The brachytic stem trait (sb1 sb2) reduces plant stature while maintaining the number of nodes for fruiting and may be desirable in the development of lodging‐resistant cultivars. To determine the effects of brachytic stem on seed yield, plant height, and other agronomic traits across a range of environments, this trait was backcrossed into ‘Wright’ and ‘GaSoy 17’, and the near‐isogenic lines (isolines) were evaluated in 57 (Wright) and 36 (GaSoy 17) environments. Averaged across environments, the height of brachytic Wright (B‐Wright) was 56% of its normal‐stemmed isoline and that of brachytic GaSoy 17 (B‐GaSoy 17) was 66% of its isoline. In a combined analysis over environments, brachytic genotypes averaged 37% shorter internode length, 5% fewer nodes, and 7% smaller seed weight than normal‐stemmed isolines. Brachytic and normal‐stemmed isolines did not differ in yield, seed protein concentration, or seed oil concentration. There was a genotype x environment interaction (P < 0.01) for yield for both isoline pairs. Regression analysis of yield stability indicated that the GaSoy 17 isolines were equally stable across environments (similar coefficients and R2 values). For B‐Wright, however, a smaller regression coefficient (b = 0.82 ± 0.07) than Wright (b = 1.07 ± 0.05) and a lower R2 value (70 vs. 89%) suggest that Wright yielded higher in favorable environments and was more stable in yield performance. Plant height of brachytic lines was much less stable than for normal‐stemmed lines. Genotypes with the brachytic stem trait produced yields similar to normal‐stemmed genotypes in environments not highly conducive to lodging. The reduced stability of yield and plant height for brachytic‐stemmed genotypes must be considered (along with the expected increase in yield in lodging‐prone environments) prior to commercial acceptance.

Soybean rust (SBR), caused by Phakopsora pachyrhizi, is a damaging fungal disease of soybean (Glycine max). Although solar radiation can reduce SBR urediniospore survival, limited information is available on how solar radiation affects SBR progress within soybean canopies. Such information can aid in developing accurate SBR prediction models. To manipulate light penetration into soybean canopies, structures of shade cloth attenuating 30, 40, and 60% sunlight were constructed over soybean plots. In each plot, weekly evaluations of severity in lower, middle, and upper canopies, and daily temperature and relative humidity were recorded. Final plant height and leaf area index were also recorded for each plot. The correlation between amount of epicuticular wax and susceptibility of leaves in the lower, middle, and upper canopies was assessed with a detached leaf assay. Final disease severity was 46 to 150% greater in the lower canopy of all plots and in the middle canopy of 40 and 60% shaded plots. While daytime temperature within the canopy of nonshaded soybean was greater than shaded soybean by 2 to 3°C, temperatures recorded throughout typical evenings and mornings of the growing season in all treatments were within the range (10 to 28.5°C) for SBR development as was relative humidity. This indicates temperature and relative humidity were not limiting factors in this experiment. Epicuticular wax and disease severity in detached leaf assays from the upper canopy had significant negative correlation (P = 0.009, R = -0.84) regardless of shade treatment. In laboratory experiments, increasing simulated total solar radiation (UVA, UVB, and PAR) from 0.15 to 11.66 MJ m(-2) increased mortality of urediniospores from 2 to 91%. Variability in disease development across canopy heights in early planted soybean may be attributed to the effects of solar radiation not only on urediniospore viability, but also on plant height, leaf area index, and epicuticular wax, which influence disease development of SBR. These results provide an understanding of the effect solar radiation has on the progression of SBR within the soybean canopy.

Asian soybean rust (ASR) is one of the most important diseases in soybean and is responsible for large economic losses. However, the use of tolerant genotypes is a sustainable strategy to address this issue. The aims of this study were to evaluate the tolerance to ASR across agronomic traits and to characterize the genetic control of the tolerance to this disease. We evaluated 257 inbreed lines from North Carolina Design II between four exotic parents and five adapted ones over F5:6 and F5:7 generations in management practices with and without ASR control. The traits seed yield (SY), hundred-seed weight (HSW), number of days to maturity (NDM), plant height at maturity, and agronomic value (AV) were considered to perform the rust difference (RD) index, analysis of variance, combining ability, and correlations. The SY, HSW, and NDM were significant to the line × management interaction, enabling selection for tolerance, and 44.7% of the lines demonstrated simultaneous tolerance to these traits based on the RD significance parameter. The correlations between the RD indices were nonsignificant with the exception of the RD for SY and AV. Our results suggest that the SY for the inbred lines is controlled by additive and parental additive-by-additive epistatic effects, while the tolerance for the SY is controlled by recombinant additive-by-additive epistatic effects. In addition, the results indicate that tolerance to Asian soybean rust occurs with different traits that are independent from one another. Therefore, tolerance should be addressed using a multitrait approach.

Genetic variability information on any crop germplasm is imperative for conservation and effective utilization in the breeding program. The field experiment was conducted to estimate the extent of genetic variability of 64 soybean genotypes for grain yield and other agronomic traits at Jimma and Metu in 2017 and 2018 main cropping seasons. The trial was laid down using 8×8 simple lattice design. The data was subjected to statistical analysis using R-software. The combined analysis of variance revealed the presence of significant (P<0.01) and wide range of variation among the tested genotypes for all of the traits. Based on the mean performance, latest maturing genotype was PI567104B (145 days), while the earliest was PI615437 (105 days). Genotype, PI567104B was the tallest in plant height (149.01 cm) while the shortest was PI507004 (44.24cm). Genotype PI567090 was found moderately susceptible in soybean rust (25.52%), while genotypes PI594538A was found the most tolerant (3.78%). Maximum hundred seed weight (24.01gm) was found from genotype PI506677, whereas the minimum seed weight (8.32gm) was recorded from genotype PI567068A. Coker240 scored maximum grain yield (3.09 t/ha) followed by genotype PI567104B (3.00 t/ha), while the minimum yield was scored from PI416826A (1.33tha^-1). Cluster analysis categorized 64 soybean genotypes into five clusters. The maximum inter cluster distance was found between clusters-I and V, suggesting best recombinants can be found by crossing genotypes in these clusters. Principal component analysis (PCA) revealed that, the 1^st four PCA with Eigen values exceeding one were responsible for about 88.74% of the total variation. Out of the entire variations, 1^stPCA and the 2^ndPCA accounted for more than two third of the total variations (68.47%). Generally, the present study indicated the existence of enormous genetic variability among soybean genotypes for various important morphological traits. Therefore, information and genetic variability obtained in this finding could be used to plan conservation, effective crossing and line selection in soybean variety improvement programs.

The aim of this study was to evaluate the effect of genotype x harvest interactions on different agronomic traits, the genetic correlation between traits in early selection under water stress, and early selection in cassava. 25 cassava genotypes were evaluated in a randomized block experimental design with four replications. The variables root weight (RW), root number per plant (RN), root diameter (RD), root length (RL), root dry matter content (DMC), stem number per plant (SN), plant height (PH), stem diameter (SD), mite severity (MS), and harvest index (HI) were evaluated under water stress conditions in two harvests. Broad-sense heritability (h²), realized heritability ( ( h R 2 )), and the index of coincidence (IC) were estimated. Accuracy estimates ranged from 0.62 for RL to 0.86 for DMC. A significant genotype effect was identified on all traits, except for RW, RL and SD. Significant genotype x harvest interactions occurred for the variables SN, PH, SD, and HI. (h²) estimates ranged from 0.27 for RL to 0.79 for SN. The estimates of the index of coincidence ranged from 100% to 25%. A positive correlation was observed between all variables under study, except for MS, RN and SN, and the other traits. The genotypes showed similar performance in the two harvests for most variables, except for SN, PH, SD, and HI.

This study aims to determine the effect of giving several organic fertilizer formulations to the intensity of soybean leaf rust disease and its production, which in turn can increase farmers' income in this area. The study was conducted using randomized block design (RBD) with 3 replications. The treatments were husk ash, compost, chicken manure, and goat manure. The parameters observed included leaf rust disease intensity, disease progression rate, plant height, number of leaves, number of branches, weight of 100 seeds and weight of seeds per plot. Data analysis was performed using Analysis of Variance (ANOVA), if the treatment has a significant effect, it is followed by the DMRT test at the 95% level. The result showed that (1) the fertilizer formulation given caused different responses to the parameters of soybean rust disease intensity, plant height, number of leaves, number of branches, weight per 100 seeds and weight of seeds per plot, (2) The best fertilizer for controlling soybean leaf rust disease is goat manure, and (3) the best fertilizer formulation to produce production is abusekam with a production of 2156.66 gr / plot (equivalent to 3.594 tons / ha)

Grain yield is one of the most important goals in wheat breeding, and agronomic or yield-related traits can directly reflect the characteristics of varieties. In order to determine the evolution of genetic diversity in agronomic traits of Xinjiang winter wheat varieties and their adaptabilities to different ecological environments, 134 winter wheat landraces and 54 moderns bred varieties from Xinjiang were selected for agronomic trait investigation. They were planted in three different ecological environments (Urumqi and Yining in Xinjiang province, and Tai’an in Shandong province) for two consecutive growth seasons, and nine agronomic and yield-related traits were surveyed and analyzed. The estimated broad sense heritability of nine agronomic and yield traits was in descending order: plant height &gt; grain width &gt; grain length/width ratio &gt; spike length &gt; spikelet number &gt; thousand- kernel weight &gt; grain number per spike &gt; grain length &gt; fertile spikelet number. Correlation analyses of nine agronomic and yield traits showed that these traits were correlated with each other. It was found that the plant height, spike length and grain length/width ratio of landraces were higher than that in modern bred varieties, but the grain number per spike, thousand kernel weight, grain length and grain width in landraces were less than that in modern bred varieties. However, the correlation coefficient of these nine traits was higher in modern bred varieties than that in landraces. These variations reflected the evolution of Xinjiang winter wheat varieties in agronomic traits in recent years. This study may provide important information for breeders to select the breeding parents in different winter wheat regions.

Two S2 or S1‐derived families from each of 118 S0 plants from Purdue random‐mated population (PP18) of Sorghum bicolor (L.) Moench, were evaluated in a randomized complete‐block design over 1 or 2 years. Genetic parameters were estimated for days to bloom, plant height, lodging, panicle compactness, panicle weight, kernel weight, weathering, hardness, and vitreosity to assess breeding potential of the population. Additive variances were estimated using a weighted least‐squares procedure. Additive variances were significant for all traits. The additive genetic coefficients of variation ranged from 2.9% for days to bloom to 25.5% for lodging. Narrow‐sense heritabilities ranged from 0.349 to 0.734 for S0‐derived family selection (unit equals mean of S2 progeny of two S1/S0 plants in two replicatio/ts in either 1 or 2 years). Heritabilities ranged from 0.359 to 0.842 for S1‐derived family selection (unit equals mean of S2 progeny of a single S1/S0 plant in two replications in either 1 or 2 years). Additive genetic (−0.737 to 0.839) and phenotypic (−0.649 to 0.710) correlations were high among agronomic traits and among quality traits, and low between agronomic and quality traits. Kernel hardness had strong correlations with weathering (negative) and vitreosity (positive). Direct selection responses (percentage of mean) ranged from 3.70 to 28.58% and from 5.10 to 37.10% for S0‐ and S1‐derived family selection, respectively, Correlated responses were lower than direct responses for most traits. However, for some pairs of traits the difference between the two responses was not large. The results suggested good potential for conventional breeding methods and early generation selection for all traits tested. More improvement would be expected from S1‐derived than from S0‐derived family selection.

Agronomic and quality traits in alfalfa are very important to forage industry. Genomic prediction (GP) based on genotyping-by-sequencing (GBS) data could shorten the breeding cycles and accelerate the genetic gains of these complex traits, if they display moderate to high prediction accuracies. The aim of this study was to investigate the predictive potentials of these traits in alfalfa. A total of 322 genotypes from 75 alfalfa accessions were used for GP of the agronomic and quality traits, which were related to yield and nutrition value, respectively, using BayesA, BayesB, and BayesCπ methods. Ten-fold cross validation was used to evaluate the accuracy of GP represented by the correlation between genomic estimated breeding value (GEBV) and estimated breeding value (EBV). The accuracies ranged from 0.0021 to 0.6485 for different traits. For each trait, three GP methods displayed similar prediction accuracies. Among 15 quality traits, mineral element Ca had a moderate and the highest prediction accuracy (0.34). NDF digestibility after 48 h (NDFD 48 h) and 30 h (NDFD 30 h) and mineral element Mg had prediction accuracies varying from 0.20 to 0.25. Other traits, for example, fat and crude protein, showed low prediction accuracies (0.05 to 0.19). Among 10 agronomic traits, however, some displayed relatively high prediction accuracies. Plant height (PH) in fall (FH) had the highest prediction accuracy (0.65), followed by flowering date (FD) and plant regrowth (PR) with accuracies at 0.52 and 0.51, respectively. Leaf to stem ratio (LS), plant branch (PB), and biomass yield (BY) reached to moderate prediction accuracies ranging from 0.25 to 0.32. Our results revealed that a few agronomic traits, such as FH, FD, and PR, had relatively high prediction accuracies, therefore it is feasible to apply genomic selection (GS) for these traits in alfalfa breeding programs. Because of the limitations of population size and density of SNP markers, several traits displayed low accuracies which could be improved by a bigger reference population, higher density of SNP markers, and more powerful statistic tools.

This study was conducted to determine the ability of additional ultrasound measures to enhance the prediction accuracy of retail product and trimmable fat yields based on weight and percentage. Thirty-two Hereford-sired steers were ultrasonically measured for 12th-rib fat thickness, longissimus muscle area, rump fat thickness, and gluteus medius depth immediately before slaughter. Chilled carcasses were evaluated for USDA yield grade factors and then fabricated into closely trimmed, boneless subprimals with 0.32 cm s.c. fat. The kilogram weight of end-point product included the weight of trimmed, boneless subprimals plus lean trim weights, chemically adjusted to 20% fat, whereas the fat included the weight of trimmed fat plus the weight of fat in the lean trim. Prediction equations for carcass yield end points were developed using live animal or carcass measurements, and live animal equations were developed including ultrasound ribeye area or using only linear measurements. Multiple regression equations, with and without ultrasound rump fat thickness and gluteus medius depth, had similar R2 values when predicting kilograms of product and percentages of product, suggesting that these alternative variables explained little additional variation. Final unshrunk weight and ultrasound 12th-rib fat thickness explained most of the variation when predicting kilograms of fat. Rump fat and gluteus medius depth accounted for an additional 10% of the variation in kilograms of fat, compared with the equation containing final weight, ultrasound ribeye area, and ultrasound 12th-rib fat thickness; however, the two equations were not significantly different. Prediction equations for the cutability end points had similar R2 values whether live animal ultrasound measurements or actual carcass measurements were used. However, when ultrasound ribeye area was excluded from live animal predictions, lower R2 values were obtained for kilograms of product (0.81 vs 0.67) and percentages of product (0.41 vs 0.17). Conversely, the exclusion of ultrasound ribeye area had little effect on the prediction accuracy for kilograms of fat (0.75 vs 0.74) and percentage fat (0.50 vs 0.40). These data substantiate the ability of live animal ultrasound measures to accurately assess beef carcass composition and suggest that the alternative ultrasound measures, rump fat and gluteus medius depth, improve the accuracy of predicting fat-based carcass yields.

Four mass‐selected populations of maize (Zea mays L.), the base population ‘Hays Golden’ (H.G.), and a double cross hybrid check ‘Nebr. 501D’ were evaluated in a range of environments involving five locations and 3 years. The four mass‐selected populations were: C15, the 15th generation of selection for high grain yield; I15, the 15th generation of selection for high grain yield following treatment with thermal neutrons in early cycles of selection; P10, the 10th generation of selection for increased prolificacy; and I14E3, the third generation of selection for yield plus earliness, low ear height, and stalk quality after 14 generations of selection for only high grain yield following irradiation with thermal neutrons.Mass selection significantly increased grain yield 12 to 15% on the average. When selection was for high grain yield only, correlated increases occurred in prolificacy, days to flower, plant and ear height, and gram mmsture at harvest. Selection for earliness and low ear height in a population previously selected for high grain yield seemed effective without reducing yield. Ten cycles of selection for prolificacy were about as effective in in. creasing yield as 15 generations of selection for yield itself. At the same time, grain moisture did not change and days to flower, plant height and ear height increased less than in selection for yield.Responses to environment mean yields were all linear and were much greater in mass‐selected populations than in H.G. or in the Nebr. 501D hybrid. Selection appears to have increased the frequencies of those genes which permit genotypes to take advantage of more favorable growing conditions. Under low yield levels caused by heat and drouth, the original population performed as well as or better than mass‐selected populations. However, when grown under favorable conditions, mass‐selected populations had substantially greater yields. Differences in yield responses under varying environments may be related to correlated responses that have occurred in mass selection programs.

As the sole plant source of many potent alkaloids, opium poppy (Papaver somniferum L.) is an important medicinal crop. Nevertheless, few studies have characterized opium poppy germplasm with crop-specific molecular markers. Because Turkey is a diversity center for opium poppy, Turkish germplasm is a valuable genetic resource for association mapping studies aimed at identifying QTLs controlling morphine content and agronomic traits. In this study, the morphological diversity and molecular diversity of 103 Turkish opium poppy landraces and 15 cultivars were analyzed. Potentially useful morphological variation was observed for morphine content, plant height, and capsule index. However, the landraces exhibited limited breeding potential for stigma number, and seed and straw yields. Both morphological and molecular analyses showed distinct clustering of cultivars and landraces. In addition, a total of 164 SSR and 367 AFLP polymorphic loci were applied to an opium poppy association mapping panel composed of 95 opium poppy landraces which were grown for two seasons. One SSR and three AFLP loci were found to be significantly associated with morphine content (P < 0.01 and LD value (r 2) = 0.10–0.32), and six SSR and 14 AFLP loci were significantly associated with five agronomic traits (plant height, stigma number, capsule index, and seed and straw yields) (P < 0.01 and LD value (r 2) = 0.08–0.35). This is the first report of association mapping in this crop. The identified markers provide initial information for marker-assisted selection of important traits in opium poppy breeding.

Asian soybean rust (ASR) is one of the most serious diseases for soybean crops, and it can be responsible for severe yield reduction. Due to the low durability of vertical resistance, studies on horizontal resistance are important for breeding programs. The objective of this study was to identify quantitative trait loci (QTLs) related to ASR horizontal resistance. A genetic linkage map with 26 groups was generated for simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers from 163 recombinant inbred lines (RILs). We found 13 QTLs related to 12 traits, including eight directly related to plant resistance. Furthermore, two QTLs controlling more than one trait were observed: one was related to agronomical traits, and another was related to a similar region of the Rpp3 locus associated with the number of uredinia and sporulation levels. These results will be useful for breeding programs to generate cultivars resistant to ASR.

Response to divergent mass selection for plant architecture and earliness and its effect on seed yield in Dimorphotheca pluvialis