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Cauliflower is a crop with intricate developmental transitions influenced by both external and internal cues. Plant growth regulators (PGRs) play a key role in developmental transitions and plant responses to environmental factors. The present study aimed to investigate the endogenous levels of gibberellins (GAs) (i) at six different developmental stages and (ii) at four time points in four varieties of cauliflower using high-performance liquid chromatography (HPLC). The Pusa Ashwini, Pusa Sharad, Pusa Shukti, and Pusa Snowball Kt-25 varieties represent all four thermosensory-based maturity groups: early (20–27 °C), mid-early (15–20 °C), mid-late (12–16 °C), and late or snowball (10–16 °C), respectively. GA 3 content was highest in Pusa Shukti (4.020 ppm) and lowest in Pusa Ashwini (3.091 ppm). A higher endogenous GA 3 concentration was recorded at the bolting stage (4.118 ppm), seedling stage (4.057 ppm), and curd initiation stage (3.722 ppm), suggesting its role in stalk elongation. The difference in GA 3 content was significant between curd (3.613 ppm) and leaf tissues (2.947 ppm) at the full curd stage and nonsignificant between stalk (3.948 ppm) and leaf tissues (4.118 ppm) at the bolting stage. Regarding the time points, the GA 3 content was highest in Pusa Sharad (4.311 ppm) and lowest in Pusa Ashwini (2.990 ppm). GA 3 content showed a significant positive correlation with duration to crucial developmental transitions, namely the curd initiation stage, the full curd stage, and the bolting stage. The study highlights the role of endogenous gibberellins in plant development and suggests their potential for benefiting seed production.

The response to selection in any crop improvement program depends on the degree of variance and heritability. The objective of the current study was to explain variance and heritability components in Indian mustard Brassica juncea (L). Czern & Coss to recognize promising genotypes for effective breeding. Two hundred and eighty-nine diverse accessions of Indian mustard belonging to four continents were analyzed for yield and yield-related traits (20 traits) over two seasons (2017–2018 and 2018–2019) using an alpha lattice design. The genetic variance was found to be significant ( P ≤ 0.01) for the individual and under pooled analysis for all of the evaluated traits, demonstrating the presence of significant genetic variability in the diversity panel, which bids greater opportunities for utilizing these traits in future breeding programs. High heritability combined with high genetic advance as percent of mean and genotypic coefficient of variation was observed for flowering traits, plant height traits, seed size, and seed yield/plant; hence, a better genetic gain is expected upon the selection of these traits over subsequent generations. Both correlation and stepwise regression analysis indicated that the main shoot length, biological yield, total seed yield, plant height up to the first primary branch, seed size, total siliqua count, days to flowering initiation, plant height at maturity, siliquae on the main shoot, main shoot length, and siliqua length were the most significant contributory traits for seed yield/plant. Also, promising genotypes were identified among the diversity panel, which can be utilized as a donor to improve Indian mustard further. These results indicated a greater scope for improving seed yield per plant directly through a selection of genotypes having the parsimonious combination of these nine traits.

In Indian mustard, improving agro-morphological and quality traits through conventional methods are both cumbersome and resource-intensive. Marker-aided breeding presents a promising solution to these challenges. Hence, the present research aimed to identify genomic regions governing agro-morphological and quality traits using genome-wide association studies (GWAS). The GWAS panel comprised 142 diverse genotypes of Indian mustard were evaluated for 20 different agro-morphological and quality traits, revealing significant difference among genotypes. Subsequently, the GWAS panel genotyped using the Brassica 90K SNP array (Illumina). Structure and diversity analysis grouped the GWAS panel into 3 sub-populations or groups, and LD decay of 1.05 Mb was confirmed through genotypic analysis. GWAS using the BLINK model revealed a total of 49 marker-trait associations (MTAs), in which 28 and 21 MTAs were observed during rabi 2020–21 and rabi 2021–22 for various agro-morphological and quality traits, respectively. Amongst them, twelve MTAs demonstrated stable associations with the studied traits, including days to 50% flowering (DF), days to 100% flower termination (DFT), days to maturity (DM), plant height (PH), main shoot length (MSL), siliqua length (SL), seeds per siliqua (SPS), oil content (OC), and glucosinolates content (Glu) in both years. Moreover, in silico analysis of nearby regions of these stable SNPs revealed their association with 31 candidate genes known to be involved in various molecular, physiological, and biochemical pathways relevant to the studied traits. These genes can be further characterized and deciphered for more precise utilization in breeding programs in the future.

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 Rabi 2019-20. 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.

Abstract Curd initiation and development are complex traits and highly responsive for different temperature ranges in cauliflower. The present study was aimed to identify QTLs for eight traits associated with curding behaviour in diverse germplasm of Indian cauliflower. For this, 92 genotypes of cauliflower and 2 each of tropical broccoli and cabbage were genotyped through genotyping by sequencing (GBS). It generated ≈302 million reads (9.1226E + 10 bp) and identified 35,381 SNPs, maximum from chromosome 3 (4735) with a mean value of 3981.1 SNPs. Ts/Tv ratio was 1.74, suggesting transition bias. STRUCTURE analysis revealed delta value of K = 4 and four subpopulations and prominence of population admixture. In total, 121 significant SNPs were detected for eight traits, 38 for Delhi (North Indian plain) and 83 for Barapani (North-East India). Twelve QTLs were detected for traits associated with regulation of curd formation and development, five of which were for marketable curd length, curd width, days to 50% curd harvest and marketable curd weight from Delhi region and seven for curd length, curd width, days to 50% curd harvest, gross plant weight, leaf length, marketable/net curd weight and number of leaves per plant for Barapani area of North East India. The SNPs identified will be useful for development of markers for curding-related traits and their use in breeding varieties with wider curding plasticity.

Seed coat colour is an important trait in Indian mustard. Breeding for seed coat colour needs precise knowledge of mode of inheritance and markers linked to it. The present study was focussed on genetics and development of functional markers for seed coat colour. F 1 s (direct and reciprocal) and F 2 populations were developed by crossing two contrasting parents for seed coat colour (DRMRIJ-31, brown seeded and RLC-3, yellow seeded). Phenotypic results have shown that the seed coat colour trait was under the influence of maternal effect and controlled by digenic-duplicate gene action. Further, Bju.TT8 homologs of both parents (DRMRIJ-31 and RLC-3) were cloned and sequenced. Sequencing results of Bju.TT8 homologs revealed that in RLC-3, gene Bju.ATT8 had an insertion of 1279bp in the 7 th exon; whereas, gene Bju.BTT8 had an SNP (C→T) in the 7 th exon. These two mutations were found to be associated with yellow seed coat colour. Using sequence information, functional markers were developed for both Bju.TT8 homologs, validated on F 2 population and were found highly reliable with no recombination between the markers and the phenotype. Further, these markers were subjected to a germplasm assembly of Indian mustard, and their allelic combination for the seed coat colour genes has been elucidated. The comparative genomics of TT8 genes revealed high degree of similarity between and across the Brassica species, and the respective diploid progenitors in tetraploid Brassica species are the possible donors of TT8 homologs. This study will help in the marker-assisted breeding for seed coat colour, and aid in understanding seed coat colour genetics more precisely.

In the era of global warming, heat stress, particularly at the seedling stage, is a major problem that affects the production and productivity of crops such as mustard that are grown in cooler climates. Nineteen mustard cultivars were exposed to contrasting temperature regimes—20 °C, 30 °C, 40 °C and a variable range of 25–40 °C—and evaluated for changes in physiological and biochemical parameters at the seedling stage to study their role in heat-stress tolerance. Exposure to heat stress showed detrimental effects on seedling growth as revealed by reduced vigor indices, survival percentages, antioxidant activity and proline content. The cultivars were grouped into tolerant, moderately tolerant and susceptible based on the survival percentage and biochemical parameters. All the conventional and three single-zero cultivars were found to be tolerant and moderately tolerant, respectively, while double-zero cultivars were reckoned to be susceptible except for two cultivars. Significant increases in proline content and catalase and peroxidase activities were found associated with thermo-tolerant cultivars. More efficient antioxidant system activity and proline accumulation were noticed in conventional along with three single-zero (PM-21, PM-22, PM-30) and two double-zero (JC-21, JC-33) cultivars that might have provided better protection to them under heat stress than the remaining one single- and nine double-zero cultivars. Tolerant cultivars also resulted in significantly higher values of most of the yield attributing traits. Heat-stress-tolerant cultivars could easily be selected based on the survival percentage, proline and antioxidants at the seedling stage and included as efficient cultivars in breeding programs.

Tocopherol is vital for the nutritional value and stability of Indian mustard (Brassica juncea L. Czern and Coss) oil; nonetheless, the lack of information on genetic control is hampering its improvement. In this study, six populations (P1, P2, F1, F2, BC1P1, and BC1P2) of RLC3 × NPJ203 were evaluated in a family block design to evaluate the inheritance pattern, gene effects, and various other genetic parameters of tocopherol content (α, γ, and total), using generation mean analysis. The comparison of direct and reciprocal crosses indicated that the tocopherol content was not influenced by maternal inheritance. Negative directional heterosis showed that ATC, GTC, and TTC are governed by recessive genes. Potence ratio and degree of dominance highlighted an over-dominance type of gene interaction for GTC and TTC, whereas ATC was governed by epistatic interactions. Furthermore, the six-parameter model revealed a duplicate gene action for α-tocopherol content. Broad and narrow sense heritability coupled with genetic advances were high.

Cauliflower is a crop with intricate developmental transitions influenced by both external and internal cues. Plant growth regulators (PGRs) play a key role in developmental transitions and plant responses to environmental factors. The present study aimed to investigate the endogenous levels of gibberellins (GAs) (i) at six different developmental stages and (ii) at four time points in four varieties of cauliflower using high-performance liquid chromatography (HPLC). The Pusa Ashwini, Pusa Sharad, Pusa Shukti, and Pusa Snowball Kt-25 varieties represent all four thermosensory-based maturity groups: early (20-27 °C), mid-early (15-20 °C), mid-late (12-16 °C), and late or snowball (10-16 °C), respectively. GA.sub.3 content was highest in Pusa Shukti (4.020 ppm) and lowest in Pusa Ashwini (3.091 ppm). A higher endogenous GA.sub.3 concentration was recorded at the bolting stage (4.118 ppm), seedling stage (4.057 ppm), and curd initiation stage (3.722 ppm), suggesting its role in stalk elongation. The difference in GA.sub.3 content was significant between curd (3.613 ppm) and leaf tissues (2.947 ppm) at the full curd stage and nonsignificant between stalk (3.948 ppm) and leaf tissues (4.118 ppm) at the bolting stage. Regarding the time points, the GA.sub.3 content was highest in Pusa Sharad (4.311 ppm) and lowest in Pusa Ashwini (2.990 ppm). GA.sub.3 content showed a significant positive correlation with duration to crucial developmental transitions, namely the curd initiation stage, the full curd stage, and the bolting stage. The study highlights the role of endogenous gibberellins in plant development and suggests their potential for benefiting seed production.