GRAIN YIELD OF SOYBEAN VARIETIES OF DIFFERENT MATURITY GROUPS IN THE FOREST-STEPPE ZONE OF THE MIDDLE VOLGA REGION

The experiments were carried out in non-watering conditions of the forest-steppe of the middle Volga region in the fields of Samara Research Institute in 2016-2018. The purpose of the research is to study the features of grain yield formation in soybean varieties of different maturity groups in order to create new varieties of Volga ecotype with high and stable grain yield. The material for the study was 29 soybean varieties of different agroecotypes and maturity groups. Standard is Samer 3. Observations and records were carried out according to the generally accepted methodology. Meteorological conditions in 2016-2018 characterized as arid, the hydrothermal coefficient varied from 0.5 to 0.7. On average, over the years of testing, the studied varieties were classified as very early – with a vegetation period of 86…90 days (8 varieties) and early 91…109 days (21 varieties), including the Samer 3 standard, ripeness groups. The high grain yield over the years of testing was in the early ripeness group - 1.95 t/ha. The sum of active temperatures above 10°C (r=+0.993…+0.999) and the amount of precipitation (r=+0.845…+0.939) had a significant impact on the duration of vegetation of both groups of ripeness in all years. A significant influence of the hydrothermal coefficient and the average daily temperature on the duration of vegetation was, revealed in 2017 and 2018. The correlation of vegetation duration with the hydrothermal coefficient was r=-0.767…-0.977, and with an average daily temperature of r=-0.902…-0.970. Among the varieties of different groups of ripeness, high seed yields (2.00…2.21 t/ha) on average over the years of testing had: Oressa, Swapa, Samer 1, Lira, Cordoba, Lisbon, Malaga

GRAIN YIELD OF SOYBEAN VARIETIES OF DIFFERENT MATURITY GROUPS IN THE FOREST-STEPPE ZONE OF THE MIDDLE VOLGA REGION

The experiments were carried out in non-watering conditions of the forest-steppe of the middle Volga region in the fields of Samara Research Institute in 2016-2018. The purpose of the research is to study the features of grain yield formation in soybean varieties of different maturity groups in order to create new varieties of Volga ecotype with high and stable grain yield. The material for the study was 29 soybean varieties of different agroecotypes and maturity groups. Standard is Samer 3. Observations and records were carried out according to the generally accepted methodology. Meteorological conditions in 2016-2018 characterized as arid, the hydrothermal coefficient varied from 0.5 to 0.7. On average, over the years of testing, the studied varieties were classified as very early – with a vegetation period of 86…90 days (8 varieties) and early 91…109 days (21 varieties), including the Samer 3 standard, ripeness groups. The high grain yield over the years of testing was in the early ripeness group - 1.95 t/ha. The sum of active temperatures above 10°C (r=+0.993…+0.999) and the amount of precipitation (r=+0.845…+0.939) had a significant impact on the duration of vegetation of both groups of ripeness in all years. A significant influence of the hydrothermal coefficient and the average daily temperature on the duration of vegetation was, revealed in 2017 and 2018. The correlation of vegetation duration with the hydrothermal coefficient was r=-0.767…-0.977, and with an average daily temperature of r=-0.902…-0.970. Among the varieties of different groups of ripeness, high seed yields (2.00…2.21 t/ha) on average over the years of testing had: Oressa, Swapa, Samer 1, Lira, Cordoba, Lisbon, Malaga

Environmental Variability of Thousand Kernel Weight in Maize Hybrids of Different Maturity Groups

Thousand kernel weight (TKW) is an important yield component trait affected by the environmental conditions. This study’s objectives were to determine an environmental variability for the TKW in 32 maize hybrids, sorted in four FAO maturity groups (FAO300, 400, 500 and 600), and to compare 12 environments in Croatia (six locations in two years) according to the joint linear regression and stability analyses across the maturity groups. In general, the effects of the environment, genotype, and their interaction (GEI) were significant. A three-factor ANOVA revealed the greatest and highly significant year effect, while the location effect was non-significant across all four FAO groups. A stability analysis did not detect any preferences with regard to the locations and trends across the FAO groups. It indicates that all locations in the Pannonian region included in this study were suitable for an evaluation of the TKW in maize genotypes belonging to all maturity groups. The TKW seems to be an appropriate yield-component trait for maize breeding due to a high heritability and linear GEI nature.

Agro-morphological and molecular diversity in different maturity groups of Indian cauliflower (Brassica oleracea var. botrytis L.)

The present study analysed the molecular and agro-morphological diversity in a set of 92 diverse cauliflower genotypes and two each of cabbage and broccoli. Field evaluation of the genotypes was done in randomized block design (RBD) at two locations (i.e. IARI, New Delhi and ICAR-RC-NEH Region, Barapani) during Rabi2019-20. Genotypes showed variation for all the eight observed traits at both locations and, the differences in early and snowball groups were distinct. Pusa Meghna, DC-33-8, Pusa Kartiki and CC-14 were earliest for curd initiation. Genotypes showed higher values for curd traits at Delhi. Molecular diversity was detected with 90 polymorphic simple sequence repeats (SSR). Number of alleles ranged from 1 to 9 with mean value of 2.16 and the highest polymorphic information content (PIC) value was observed for primer BoGMS0742 (0.68) with a mean value of 0.18. Cluster analysis using agro-morphological traits substantiated classification of the genotypes for maturity groups. However, SSR analysis revealed four clusters and with a composite pattern of genotype distribution. STRUCTURE analysis also supported the admixture and four subpopulations. The studyindicates for introgression of genetic fragments across the maturity groups, thereby, potential for use in further genetic improvement and heterosis breeding.

Assessment of climate change impact on different pigeonpea maturity groups in north Indian condition

The CROPGRO-pigeonpea model embedded in DSSAT v4.7.5 was used to assess the impact of climate change on phenology and grain yield of reference genotype of different pigeonpea maturity groups. The impact of climate change delayed reproductive stages (anthesis, maturity) and decreased grain yield of reference genotype of different pigeonpea maturity groups were evident in all scenarios. Short duration genotypes (MN5, ICPL88039, Prabhat, UPAS120) showed progressively higher decrease in yield as compared to medium (Maruti, Asha, ICP7035) and long (Bahar, MAL13) duration genotypes with each successive increase in scenatio from RCP2.6 to RCP8.5 and projected year from 2010 to 2095. Anthesis was delayed 9 days in MN5 to 20 days in Bahar and maturity delayed 15 days in MN5 to 24 days in Bahar with RCP 8.5 in year 2095 in comparison to RCP2.6 in years 2010, whereas, grain yield was decreased 14% in Bahar to 66% in MN5 among genotypes of different maturity groups.

Trends in Maize Grain Yields across Five Maturity Groups in a Long-Term Experiment with Changing Genotypes

Combining experimental studies on grain yield variability with crop model simulations in maize could assist in choosing the optimum maturity group for a certain location, counteracting the effect of climate change. However, studies considering specificities in Southeast Europe are lacking. The objectives were to put various environmental covariates including stress degree days (SDD) into FAO maturity settings to determine the impact of climate change on maize growing in Southeast Europe and to compare trends for grain yields over twenty years of maize experimental and simulation data grouped in five FAO maturity groups (FAO 200–FAO 600). Pre-registration yield trials of maize planted in one location in Croatia grown from 1996 to 2015 were used to determine “potential yield”. Correlation coefficients between 12 climate covariates and grain yield (GY) across the maturity groups revealed the tightest negative associations between SDD and GY that were weakened by later-maturity groups. Similar trends in GY were obtained by both experimental and simulation data, highlighting FAO 600 as a nearly no yield-reducing FAO group over the two decades. Our results indicate that choosing early maize hybrids in Southeast Europe does not seem to be an optimum option in the future, since these hybrids are more sensitive to omnipresent heat stress than late hybrids.

Patterns of Genetic Variation in a Soybean Germplasm Collection as Characterized with Genotyping-by-Sequencing

Genomic characterization is playing an increasing role in plant germplasm conservation and utilization, as it can provide higher resolution with genome-wide SNP markers than before to identify and analyze genetic variation. A genotyping-by-sequencing technique was applied to genotype 541 soybean accessions conserved at Plant Gene Resources of Canada and 30 soybean cultivars and breeding lines developed by the Ottawa soybean breeding program of Agriculture and Agri-Food Canada. The sequencing generated an average of 952,074 raw sequence reads per sample. SNP calling identified 43,891 SNPs across 20 soybean chromosomes and 69 scaffolds with variable levels of missing values. Based on 19,898 SNPs with up to 50% missing values, three distinct genetic groups were found in the assayed samples. These groups were a mixture of the samples that originated from different countries and the samples of known maturity groups. The samples that originated from Canada were clustered into all three distinct groups, but 30 Ottawa breeding lines fell into two groups only. Based on the average pairwise dissimilarity estimates, 40 samples with the most genetic distinctness were identified from three genetic groups with diverse sample origin and known maturity. Additionally, 40 samples with the highest genetic redundancy were detected and they consisted of different sample origins and maturity groups, largely from one genetic group. Moreover, some genetically duplicated samples were identified, but the overall level of genetic duplication was relatively low in the collection. These findings are useful for soybean germplasm management and utilization.