Duration Of Reproductive Phase Research Articles

Genetic variability parameters and character association studies among phenological traits, yield traits and quality traits under different dates of planting in chickpea (Cicer arietinum L.)

The study was conducted during rabi 2020-2021 at RARS, Nandyal, Andhra Pradesh to determine relationships among phenological traits, seed yield, yield attributes and quality traits in chickpea under different dates of planting. In the present study, in all three dates of planting, seed yield recorded highly significant and positive association with two phenological traits viz., duration of reproductive phase and duration of flowering. However, these traits were influencing seed yield via other contributing characters like days to first f lowering, duration of vegetative phase, leaf area index, days to maturity, plant height, number of branches per plant, number of pods per plant, 100 seed weight and harvest index. Strong correlations have been established between seed size and cooking time especially in kabuli and therefore, special emphasis may be given for improving the seed size with less cooking time in extra-large seeded kabuli chickpea. Further, there is sufficient genetic variability recorded for leaf area index, number of branches per plant, number of pods per plant, plant height, harvest index, seed yield, 100 seed weight, hydration capacity, swelling capacity, cooking time and iron content in the genotypes and the traits exhibited high heritability and high to moderate genetic advance in all three dates of planting.

Study of genetic diversity in Mungbean

An experiment was conducted to study heritability in broad sense, association effects, direct and indirect effect of yield attributing traits on yield among 12 green gram genotypes. ISSR markers were also used to study the genetic diversity present in the studied genotypes at molecular level. Analysis of variance for RBD indicated presence of significant amount of genetic diversity among the genotypes for all the traits. Phenotypic coefficient of variation was higher than Genotypic coefficient of variation. Path coefficient revealed that most of the yield attributing traits viz., days to 75 percent flowering, duration of reproductive phase, days to maturity, number of secondary branches per plant, number of clusters per plant, grain per pod, pod density and number of seed per pod, traits had positive direct effect on yield per plant. Two clusters were obtained from Mahalobinis D2 statistics. Traits viz., number of pods per plant, plant height, 1000-seed weight and yield per plant showed high heritability with high genetic advance.

Determination of Agronomical Characters as the Resistance Attributes of Twenty Soybean Varieties to Stink Bug (Nezara viridula L.)

The research was conducted to study the agronomical characters as the resistance attributes of twenty soybean varieties to Nezara viridula. The results showed that the twenty soybean varieties had a different response to stink bug infestation. Gepak Kuning, Seulawah, and Sinabung were resistant to stink bug, while Argomulyo were highly susceptible, and Grobogan and Malabar were susceptible. Besides resistance to stink bug, Sinabung also had the highest seed yield (2.95 t/ha). The seed yield of Gepak Kuning and Seulawah were not high, i.e. 2.20 and 1.82 t/ha respectively. The three highly susceptible or susceptible varieties also showed the lowest seed yield, i.e. 0.68 t/ha (Argomulyo), 0.42 t/ha (Grobogan) and 0.99 t/ha (Malabar). The negative correlation was shown between resistance to pest with days to maturity, duration of the reproductive phase, the number of unfilled pods, and weight of 100 seeds. Seed yield also had a negative correlation with duration of reproductive phase and weight of 100 seeds. It indicated that varieties with short duration of reproductive phase and small seed size were preferred by Nezara viridula as food sources. Therefore, these two characters can be used to determine the soybean resistance to Nezara viridula.

Genetic variability, evaluation and characterization of sunflower (Helianthus annuus L.) germplasm

Fifty accessions of sunflower germplasm were characterized and evaluated for seed yield and its components traits to study the variability present among different germplasm lines. Significant amount of genetic variability was observed for all the characters under study. Seed yield and hull content were identified for highest genotypic (27.08 and 20.14%, respectively) and phenotypic coefficients of variation (27.89 and 20.64%, respectively) and also for high heritability (97.46 and 97.28%, respectively) coupled with high genetic advance (52.19 and 40.49%, respectively) over mean followed by duration of reproductive phase, oil content, 100-seed weight and plant height. Qualitative traits also showed wide variation among the accessions. Majority of the accessions were early in flowering, medium in maturity and medium in head diameter. Among all the accessions, ten lines were observed with short height and ten lines showed high oil content (> 40%). Maximum genetic distance was observed between the accessions EC-601800 and EC- 512687 and utilization of these accessions has been advocated in breeding programme. The results of the present study can be useful for the formation of data base and reference lines, genotype identification and will also be helpful in amplification of future sunflower improvement programme.

Inheritance pattern of genes for morpho-physiological and yield traits in wheat (Triticum aestivumL.)

In order to study the inheritance pattern of morpho-physiological traits in bread wheat, a 10×10 diallel cross, excluding reciprocals was made and grown in a randomized complete block design (RCBD) with three replications. Observations were recorded on Days to 75% flowering (DF), Days to maturity (DM), Duration of reproductive phase (DRP), Plant height (cm) (PH), Effective tiller/plant (TLS), No. of spikelets per spike (SLS), No. of grains per spike (GS), Grain weight per spike (g) (GW), Spike length (cm) (SL), Biological yield per plant (g) (BY), Harvest index (%) (HI), 1000-Grain weight (g) (TGW), Spike density (SD), Canopy temperature depression (°C) (CTD), Chlorophyll intensity (%) (CI), Chlorophyll fluorescence (Fv/Fm) (CF), Protein content (%) (PC), Grain yield per plant (g) (GY). Highly significant differences were observed among the genotypes for all traits. The resulted 45 F1s and their F2s used for study the nature of gene for grain yield and its contributing traits in bread wheat. The result indicated that considerable gene action and average degree of dominance respond to achieving significant result for grain yield and its component traits. In both the generations F1s and F2s, grain yield per plant (g) was governed by non-additive gene action based on combining ability analysis, (σ2 g/σ2 s)0.5 [GCA and SCA variance ratio] and (H1/D)0.5 [Degree of dominance] were exhibited over dominance type average degree of dominance for grain yield and its component traits in both generations. Genetic analyses of the traits confirm the involvement of both additive and non-additive gene effects in governing the inheritance.

Evaluation of sunflower (Helianthus annuus L.) germplasm using multivariate statistical techniques

Evaluation of sunflower hybrids using morphological data is necessary and essential in sunflower breeding programs. The aim of this paper was to evaluate the productive possibilities of some sunflower germplasm using multivariate technique. Fifty sunflower genotypes were characterized using eleven morphological traits. Among the traits studied, high coefficient of variation was observed for duration ofreproductive phase (11.73%), seed yield per plant (11.49%), 100-seedweight (8.98%) and head diameter (8.33%). Agglomerative hierarchical clusteringmethod classified the fifty genotypes into five clusters. A large number of genotypes were placed in cluster III (22) followed by cluster I (14), cluster II (6), cluster V (6) and cluster IV (2). The maximum inter-cluster distance of 47.83 was observed between clusters I and cluster IV indicating the possibility of high heterosis. The first four principal components showed 71.61% of the total variation. The genotype EC-512687 and EC-601746 had found top rank by both the methods. The results of PCA were closely in line with those of composite indices. These results can be used by breeders in sunflower breeding program.

Estimation of genetic variance on qualitative and quantitative improvement through biometrical approach half diallel analysis in (Triticum aestivum L)

The present investigation entitled “Genetic studies for yield and its contributing character in bread wheat (Triticum aestivum L.)” was undertaken involving 100 genotypes (10 parents +45 F1s +45F2s) of a 10- parent-diallel to study the genetic parameters for some quality and quantity attributes along with its contributing traits. The diverse wheat cultivars/ genotypes and their first as well as second filial generation was studied by resolving them in genetic component analysis and selection parameters (direct and indirect parameters). The observations were recorded on 13 characters namely, days to 75% flowering, plant height, number of reproductive tiller per plant, number of spikelets per spike, spike length, number of grain per spike, days to maturity, 1000-seed weight, ear density, duration of reproductive phase, seed hardness, protein content and yield per plant. The data recorded were subjected to different analysis. Forty five crosses in F1 generation of wheat (Triticum aestivum L.) were used for studying the character association among grain yield and its related characters. The results showed that the number of grains per spike, grain weight per spike and number of productive tillers per plant were significantly and positively associated with grain yield per plant in parents and F1 cross combinations. Dickson and Jinks (1956) extended the above methods of diallel analysis, which estimated both the degree of parental heterozygosity and comparable genetic components of variation.

Grain Growth of Wheat Under Prevailing Air Temperature

An experiment was conducted at the Regional Agricultural Research Station, Ishwardi, Pabna in two consecutive years of 2010-2011 and 2011-2012 to quantify the effect of temperature on phenological duration and grain growth of wheat. Temperature variation was created by changing sowing date (15 November=S1, 30 November=S2, 15 December=S3 and 30 December=S4). Results revealed that reproductive phase was more sensitive to high temperature as compared to vegetative phase of wheat. Reproductive phase reduced from 54 to 37 days in 2010-2011 and from 64 to 34 days in 2011-2012 as influenced by higher air temperature under late sowing. Duration of reproductive phase was strongly and negatively correlated with mean air temperature (r=-0.64 to -0.96 at p<0.01). Maximum grain growth (49.12-50.18 mg grain-1) was recorded at 55 days after anthesis in 30 November sowing in both the years. Grain growth was negatively correlated (r=-0.80 at p<0.01) with mean air temperature during grain growth period. Grain yield was the highest (4560-6080 kg ha-1) in 30 November sowing, afterwards it reduced in both the years. Grain yield was negatively correlated (r=-0.70 at p<0.01) with mean air temperature of grain growth period. Rising of air temperature at grain filling stage subjected to reduced grain yield of wheat. Effect of temperature on grain yield of wheat can be explained about 88% by the function of Y= -14910+ 2069X-52.67X2 (R² = 0.88). Rising of one degree (oC) temperature above optimum (19.64 0C) grain yield reduced @ 53 kg ha-1 (0.98%).Bangladesh Agron. J. 2016 19(2): 79-85

Evaluation of Indian mustard genotypes to heat stress in irrigated environment - seed yield stability and physiological model

Indian mustard is mostly targeted for commercial cultivation as an early-sown or late-sown crop with the expectation of higher seed yield and oil content. With this lacuna, 45 genotypes were analyzed for yield traits by growing them as early, timely, and late-sown crops over 2 years in Pantnagar, India. The results of the ‘Eberhart and Russell Model’ and ‘GGE Biplot’ analyses were in accordance to each other but Eberhart and Russell’s model was more appropriate for judging the genotype(s) to environment specificity/adaptation while GGE Biplot was the best approach to evaluate the concerned environments for their discriminating power to genotypes. Inverse and counteracting relationships were observed among model parameters, i.e., crop growth rate (C), partitioning coefficient (P), and duration of reproductive phase (Dr) with seed yield and oil content. Seed yield was positively (P ≤ 0.01) related to all related traits except Dr, while oil content was positively (P ≤ 0.01) related to only Dr. Both C and P contributed to final yields, but P had a greater contribution particularly under terminal heat stress.

Association analysis for yield and component traits in sunflower (Helianthus annuus L.)

Ninety genotypes of sunflower were evaluated for the estimation of correlation and path analysis. Data were recorded for yield and its component traits viz., days to 50% flowering, days to maturity, duration of reproductive phase, plant height, stem girth, head diameter, 100-seed weight, seed filling percentage, hull content (%), protein content (%), oil content (%) and seed yield per plant (g). The seed yield per plant showed positive and significant correlation with seed filling percentage, head diameter, oil content and 100-seed weight showed negative correlation with days to 50% flowering, days to maturity and hull content. This shows that head diameter, 100-seed weight, seed filling percentage and oil content are the major yield contributing traits to be given more selection pressure for improving yield. The path coefficient analysis showed that 100-seed weight had the highest direct and positive effect on seed yield per plant followed by head diameter, plant height and oil content had positive direct effects on seed yield. So, direct selection of genotypes for seed yield through these traits may be effective.

Varietal Difference in the Duration of Reproductive Phase in Oryza sativa L.

短日条件がイネの生殖生長に与える影響をジャポニカ，インディカを含む8品種を用いて検討した．生殖生長相は幼穂形成開始（以後，幼穂形成始期と表す）から出穂までとした．短日処理区（10時間日長）と自然日長区を設け，8 L容量ポットに1株1本植えで9個体を植え，各処理区・各品種5ポットずつ栽培し，それらの幼穂形成始期と出穂期を調べた．供試した8品種から得られた結果は次のとおりである．（1）短日処理により生殖生長相は晩生＞中生＞早生の順に短くなる傾向を示した．また，各品種の生殖生長相が短日処理により短縮される期間は早生＞中生＞晩生の順で長くなる傾向が認められた．（2）分散分析の結果，供試した8品種において生殖生長相は品種間，処理区間で1％水準の有意差があることが示された．一方，TEPI，MIRITI，BINASHAILは生殖生長相が短日処理区と自然日長区で変わらないことより，生殖生長相が短日処理の影響を受けにくい品種も存在することが分かった．

Genotype-by-environment interaction effect on yield and its physiological bases in short-duration pigeonpea

Short-duration pigeonpea [ Cajanus cajan (L.) Millsp.] is being targeted for commercial cultivation in more diverse environments than traditional cultivars used in subsistence agriculture. As it is a relatively new crop, information on performance of recently evolved lines and hybrids across a range of environments is lacking. Thirty lines were compared for grain yield in 20 environments representing major areas of cultivation [Patancheru (17°N and 72°E), Gwalior (26°N and 78°E) and Hisar (29°N and 75°E)], soil types and sowing times. Grain yield across environments varied widely from 0.36 to 2.09 t ha −1. Average yield was highest, 1.53 t ha −1, for hybrid ICPH 8. The genotype-by-environment interaction (GEI) effect analyzed using the additive main effects and multiplicative interaction (AMMI) statistical model was highly significant and was three times more important than the line effects. Line ICPL 83006 was highest yielding in one, ICPL 87101 in two, hybrids ICPH 9 in four and ICPH 8 in 13 environments. Based on the range of adaptation of the highest yielding lines, the 20 environments were grouped into four fairly homogeneous crop growing environments in which the same genotypes performed best (mega-environments). The average yield with the highest-yielding lines planted in the respective mega-environment was 12.5% higher than when ICPH 8 was planted across all the environments. Significant correlations of crop growth rate, duration of reproductive phase, partitioning and growth habits of lines with GEI patterns suggest that variable performance of the lines across the 20 environments could be due to variation in the physiological components of yield. The results suggest the presence of significant GEI and that its systematic exploitation through selection of the appropriate physiological components for each mega-environment can result in higher average yield across growing environments.