Main Raceme Research Articles

Erysimum damirliense sp. nov. (Brassicaceae) from Iran

Erysimum damirliense, a new species of Brassicaceae from Zanjan and Ardebil provinces (northwest Iran) is described and illustrated. The new species resembles E. uncinatifolium and E. elbrusense, but is easily recognized by its life form, basal leaf margin, indumentum of cauline leaves, number of flowers in the main raceme, fruit width and style length. Phylogenetic analysis of internal transcribed spacer (ITS) DNA sequences confirm that the new species is distinct from morphologically similar species.

Mapping a major QTL responsible for dwarf architecture in Brassica napus using a single-nucleotide polymorphism marker approach

BackgroundKey genes related to plant type traits have played very important roles in the “green revolution” by increasing lodging resistance and elevating the harvest indices of crop cultivars. Although there have been numerous achievements in the development of dwarfism and plant type in Brassica napus breeding, exploring new materials conferring oilseed rape with efficient plant types that provide higher yields is still of significance in breeding, as well as in elucidating the mechanisms underlying plant development. Here, we report a new dwarf architecture with down-curved leaf mutant (Bndwf/dcl1) isolated from an ethyl methanesulphonate (EMS)-mutagenized B. napus line, together with its inheritance and gene mapping, and pleiotropic effects of the mapped locus on plant-type traits.ResultsWe constructed a high-density single-nucleotide polymorphism (SNP) map using a backcross population derived from the Bndwf/dcl1 mutant and the canola cultivar ‘zhongshuang11’ (‘ZS11’) and mapped the dwarf architecture with the down-curved leaf dominant locus, BnDWF/DCL1, in a 6.58-cM interval between SNP marker bins M46180 and M49962 on the linkage group (LG) C05 of B. napus. Further mapping with other materials derived from Bndwf/dcl1 narrowed the interval harbouring BnDWF/DCL1 to 175 kb in length and this interval contained 16 annotated genes. Quantitative trait locus (QTL) mappings with the backcross population for plant type traits, including plant height, branching height, main raceme length and average branching interval, indicated that the mapped QTLs for plant type traits were located at the same position as the BnDWF/DCL1 locus.ConclusionsThis study suggests that the BnDWF/DCL1 locus is a major pleiotropic locus/QTL in B. napus, which may reduce plant height, alter plant type traits and change leaf shape, and thus may lead to compact plant architecture. Accordingly, this locus may have substantial breeding potential for increasing planting density.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0865-6) contains supplementary material, which is available to authorized users.

Using a fractional factorial design to evaluate the effect of the intensity of agronomic practices on the yield of different winter oilseed rape morphotypes

Significant progress in plant breeding and molecular genetics contributed to the development of rapeseed (Brassica napus L.) genotypes/cultivars whose biomass (mainly seeds) can be used for a variety of purposes. Those advancements are also used to modify rapeseed production technologies. In systems with many production factors, agronomic measures exert direct and indirect (interaction) effects on crops and yield. Multiple production factors can be analyzed simultaneously with the use of fractional factorial sk−p designs. A field experiment a with sk−1 fractional factorial design, with 5 factors (k=5) at 3 levels (s=3), was performed at the Agricultural Experiment Station in Bałcyny (north-eastern Poland) in 2008–2011. The study investigated the responses of semi-dwarf (PR45 D03, Avenir) and long-stem (Visby) heterozygous cultivars of winter oilseed rape (WOR) to the main yield-forming factors (seeding date, seeding rate, spring nitrogen fertilization) and yield-protecting factors (fungal disease management in spring). Seeds of WOR cultivars were sown on 12 and 22 August and on 1 September at three seeding rates of 40, 60 and 80 pure live seedsm−2. Nitrogen fertilizers were applied at the rate of 80, 160, and 240kgha−1, and the plots were subjected to 0, 1 and 2 fungicide treatments. The highest yield (4.73Mgha−1) was reported for the long-stem cultivar Visby, which was 120 and 620kgha−1 higher in comparison with semi-dwarf cultivars Avenir and PR45 D03, respectively. Early sowing (12 August) was well tolerated by the semi-dwarf variety Avenir and the conventional height cultivar Visby. Early sowing led to a 6% decrease in seed yield of the semi-dwarf cultivar PR45 D03. None of the studied varieties had a positive response to sowing at the beginning of September. Delayed sowing generated more negative effects in semi-dwarf cultivars (decrease in seed yield by around 91kgha−1day−1) than in the long-stem cultivar (59kgha−1). The seeding rate of 80 pure live seedsm−2 (considerably higher than recommended for hybrid WOR cultivars) had the most beneficial influence on seed yield in all tested WOR cultivars. Nitrogen (N) fertilization exerted a yield-forming effect up to a rate of 240kgha−1 in both analyzed cultivars of WOR. The semi-dwarf cultivars and the conventional height cultivar of WOR showed identical responses to the applied fungicide treatments. Single fungicide treatment at the stage of petals falling from the main raceme was most effective. Fungicide withdrawal decreased seed yield by as much as 110kgha−1. The straw yield of semi-dwarf and conventional height cultivars of WOR was comparable because the former was characterized by a stronger branching structure and a higher number of pods. Contrary to expectations, the long-stem cultivar was characterized by a more favorable harvest index than semi-dwarf cultivars.This study relies on the 35-1 fractional factorial design which is a fast and relatively cheap method of identifying key agricultural factors and their interactions in the process of determining the yield of new cultivars. The results can also optimize decision-making in agriculture and constitute a basis for establishing effective levels of key operations in the production of new morphotypes and genotypes of agricultural crops.

Line × tester analysis in rapeseed: Identification of superior parents and combinations for seed yield and its components

Abstract The objectives of this research were to investigate the genetic structure of the 20 F1s rapeseed hybrids established from five female moderate maturing lines and four early maturing male testers, determine parents showing general combining ability (GCA) and assess crosses demonstrating specific combining ability (SCA). Significant mean squares of lines and testers determined GCA and confirmed the presence of additive genes that were influencing the traits, while the significance of line×tester interactions indicated the importance of SCA of parents and demonstrated the importance of dominance or non-additive genetic effects. Significant variance of parents vs. crosses revealed significant average heterosis for all the traits except first pod height and seeds per pod. High narrow-sense heritability estimates for number of branches and pod length indicated the importance of additive genetic effects for these traits. Significantly positive correlation was exhibited between GCA effects on pods on main raceme and seed yield and, therefore, the GCA effect on pods on main raceme can be used as indirect selection criterion for improvement of seed yield. The crosses L41×Foma2, Zafar×R42 and L22B×R38 recorded significant positive SCA effects and high mean values of seed yield of 3400, 3311.3 and 2904.2 kg ha-1, respectively.

Stepwise regression and principal component analyses for quantitative traits of rapeseed genotypes at different sowing dates

The present research was done to assess the best selection criteria for yield improvement in rapeseed (Brassica napus L.) using stepwise regression and principal component analyses at different sowing dates. All the traits except 1000-seed weight were significantly affected by sowing dates. The results of stepwise regression analysis revealed that seeds per pod had an important role at the first and second sowing dates, but at the third and fourth sowing dates, pods per plant and days to flowering were more important than other yield components for a seed yield prediction model. On the basis of a cumulative percent of variation, three principal components (PCs) were determined for each sowing date. The cumulative percentages of variation for three PCs at the first to fourth sowing dates were 0.97, 0.96, 0.89 and 0.95, respectively. At the first sowing date, the first principal component (PC1) had high positive and negative PC loading values for the studied traits such as days to flowering, days to the end of flowering, duration of flowering, pods per plant and harvest index. Therefore, there was high variation in these traits among the genotypes. PC2 of the first sowing date had also high PC loadings for pods on the main raceme, seeds per pod, 1000-seed weight, biological and seed yields, therefore the correlation of these traits with this PC will be high. In PC3 of the first sowing date, height, pods on the main raceme and pods per plant had the high value of PC loadings. Based on stepwise regression analysis, seeds per pod at the first and second sowing dates and days to flowering and pods per plant at the third and fourth sowing dates had an important role for improving seed yield.

Genetic diversity revealed by Morphological Descriptors Among Yellow Sarson Germplasm Under Timely and Late Sown Conditions

Thirty-one local germplasm lines of Brassica rapa var. yellow sarson, collected from eastern parts of Uttar Pradesh (India) were evaluated along with two commercial varieties as checks in two environmental conditions (timely sown E1 and late sown E2 conditions). Data collected on 14 morphological characters was subjected to D2 statistics. The 31 germplasm lines were classified into 8 and 12 clusters under E1 and E2, respectively. In E1, cluster I had a maximum of 15 genotypes while cluster III, VII and VIII had only one genotype each, in E2, cluster III had maximum of 15 genotypes whereas cluster IV, V, VII, VIII, X, XI, and XII had only one genotype each. Likewise, the inter-cluster average D2value was maximum (26.81) between cluster III and VIII and minimum between cluster V and I (2.80). Intra-cluster average D2 values ranged from 0.00 to 4.63. In late sown condition, the inter-cluster distance was maximum between IV and II (51.93) and minimum in cluster VI and IX (4.965). Intra-cluster average D2 value ranged from 0.0 to 4.594. The genotypes which occupied distant clusters can be used in hybridization programme as parents to recover more heterotic hybrids. Secondary branchesplant−1, glucosinolatecontent, seed yield, seeds siliqua−1, primary branches plant−1 and siliqua length contributed maximum towards total divergence in timely sown condition whereas secondary branches plant−1, seed yield, primary branches plant−1, glucosinolate content, and main raceme length were the major contributors in late sown conditions.

Variation, correlation, regression and path analyses in Eruca sativa Mill.

In the present study variation, correlation, regression and path coefficients in Eruca sativa Mill. were analyzed. Great variations were observed with agronomic and oil quality traits in Eruca. Partial correlation, stepwise regression and path analyses indicated that the contributions of siliqua number per plant (X7), seeds per siliqua (X8), 1000-seed weight (X9) and siliqua number of main raceme (X6) to seed yield per plant (Y) were highly significant and positive (P<0.01), and those of number of secondary branches (X4) and plant height (X1) were also significant and positive (P<0.05), while that of branching height (X2) was significant and negative (P<0.05). The regression formula of these agronomic traits to seed yield per plant is Y= -2.134 + 0.010X1- 0.011X2 + 0.049X4 + 0.028X6 + 0.019X7 + 0.056X8 + 0.465X9. Based on the analyses we suggest that future Eruca improvement should focus first on siliqua number per plant, then seeds per siliqua, 1000-seed weight, siliqua number of main raceme, number of secondary branches and plant height, but the negative correlations between 1000-seed weight and seeds per siliqua, 1000-seed weight and siliqua number per plant, siliqua number of main raceme and number of secondary branches should also be considered. The Eruca materials with higher plant, lower branching height, larger and yellow seeds found in this study will be valuable for future Eruca improvement. Key words: Eruca sativa, variation, simple and partial correlation, stepwise regression, path analysis.

Changes in seed weight in response to different sources: sink ratio in oilseed rape

Little knowledge exists about the degree of source, sink and source: sink limitations on mean seed weight in oilseed rape (Brassica napus L.). The objective of this work was to analyze the nature and magnitude on seed weight response to assimilate availability during the effective seed-filling period in oilseed rape. Three Argentinean varieties, Eclipse, Impulse, and Master, were grown under field conditions, and at the beginning of the effective seed filling period, a broad range of source: sink manipulation combinations were produced. Source manipulations consisted of two incoming radiation (R) level reductions: 0% (Rn) and ~50% (Rs) combined with three different sources: sink treatments were applied: C, control; PR, ~50% pod removal, and D, 100% defoliation. Rs significantly reduced yield (15%) and MSW (12%) with respect to Rn, without significant effects on the rest of the sub yield components. Source:sink manipulation treatments significantly affected all yield components. PR diminished yield by 29%, reducing ca. 40% seeds pl-1 by reductions pods pl-1 (41%) with respect to Rn, whereas PR increased MSW by 19%, counterbalancing the reduction in seeds pl-1 and thereby in yield. When considering different seed positions along the main raceme, Rs reduced MSW by 12% independently of seed positions onto the raceme. On the contrary, PR increased MSW in average 17% with respect to C. Results reported here suggest that oilseed rape has source: sink co-limitation during the effective seed filling period, which is apparently higher than wheat and lower than maize. DOI: http://dx.doi.org/10.3329/ijarit.v4i1.21091 Int. J. Agril. Res. Innov. &amp; Tech. 4 (1): 44-52, June, 2014

Genetic architecture for yield and its components in castor (Ricinus communis L.)

The genetic analysis was done through line x tester design involving five pistillate lines and 13 pollen parents for the development of a set of 65 hybrids in castor, Ricinus communis. The combining ability analysis for yield and its components revealed that both the components, additive and non-additive of genetic variances were significantly influenced by environment. The preponderance of additive gene action was observed for the control of days to 50% flowering and days to 50% maturity of main raceme as well as number of nodes up to main raceme. For the characters plant height and oil content, non-additive gene effect was propounded. The parents SKP-8, 103745, 1379, SKP-93, TMV-5, Aruna, SH-72 and SK2-8A were good general combiners for imparting earliness, former three as well as VP-1 were good general combiner for short plant stature, whereas later two and SKP-82, JH-128, SH-41 and48-1 were good general combiners for oil content. The estimates of gca effects suggested that parents SKP-93, SKP-82, 48-1, Aruna, SPS-35-9B, JI-77 and JH-128 were good general combiners for seed yield and at least for two important yield attributes viz., 100-seed weight, effective branches/plant, number of capsules in main raceme and length of main raceme. The good specific cross combinations for yield were SKP-8 x TMV-5, VP-l x SKI-41 and SKP 25 x 1379, also identified as superior hybrid for earliness, high oil content and short plant stature, respectively. Hence, these may be exploited for commercial cultivation. The hybrids SKP-8 x TMV-5, SKP-25 x JH-128 and SKP-82 x 48-1 depicted significant positive sca effect for seed yield, these hybrids could be exploitedfor development of hybrids and new inbred as well as pistilate lines in castor. The potence ratio of genetic variance suggested preponderance of non-additive gene effect for inheritance of the seed yield/plant, number of capsules in main raceme and number of effective branches.

Multivariate Regression Analyses of Yield Associated Traits in Rapeseed (Brassica napusL.) Genotypes

The efficiency of a breeding program depends mainly on the direction of the correlation between yield and its components and the relative importance of each component involved in contributing to seed yield. The interrelationships of nine quantitative traits in 28 genotypes of spring oilseed rape (days to flowering, days to end of flowering, duration of flowering, days to maturity, pods per main raceme, pods length and pods per plant, and seed yield) were computed. Significant genotypic effects were found for phenological traits, yield components, and seed yield, indicating significant genetic differences among the genotypes. High broad sense heritability was estimated for phenological traits, seeds per pod, and seed yield, signifying high selection gain for improving these traits. Path coefficient analysis revealed that days to flowering and number of pods per plant had the highest direct effects on seed yield. Duration of flowering, number of branches, pods on main raceme, pods per plant, and seed yield had high genetic coefficient of variation. The results of factor analysis showed three factors including factor 1 (phenological traits), factor 2 (primary yield components), and factor 3 (secondary yield components). The results of stepwise regression analysis revealed that pods per plant, number of branches, and duration of flowering had considerable effects on seed yield.

Genetic Diversity in Indian Mustard [Brassica juncea (L.) Czernj &amp; Cosson] as Revealed by Agronomic Traits and RAPD Markers

In present study, an attempt has been made to assess the genetic diversity among 50 genotypes of Indian mustard using agronomic traits and random amplified polymorphic DNA (RAPD) markers. Variability was observed for agronomic traits viz plant height (cm), main shoot length (cm), days to flower initiation, number of siliquae on main raceme, number of seeds per siliqua, seed yield per plot (g), biological yield per plot (g), harvest index (%), days to maturity and 1,000-seed weight (g). Cluster analysis based on agronomic traits revealed a high degree of diversity among the accessions. Maximum variability was recorded for biological yield followed by seed yield, while minimum variability was observed for days to maturity followed by days to flower initiation. RAPD marker OPB8 was found to be the most informative primer followed by OPB14, OPB11 and OPB2. Both agronomic traits and molecular markers were effective in discriminating genotypes into different clusters, however, clustering pattern varied for both agronomic traits and molecular markers. Different clustering pattern based on agronomic data and RAPD markers indicated lack of association between genetic and phenotypic diversity implying that polymorphism due to RAPD is not linked to phenotypic variation. There was no relationship between place of origin and clustering of genotypes, however, diverse genotypes could be identified on the basis of both and are likely to produce more variability in segregating generations as well as to serve as parents for high heterosis.

Combining ability analysis for seed yield and yield components in castor (Ricinus communis L.)

The genetic analysis was done through a line x tester design involving 70 castor (Ricinus communis L.) hybrids generated by crossing 5 pistillate lines with 14 pollen parents. The combining ability analysis for yield and its components revealed that both additive and non-additive genetic variance were significantly influenced by environment. The preponderance of additive gene action was observed for the control of daysto 50 % flowering and days to 50 % maturity of main raceme as well as number of nodes up to main raceme. Non-additive gene effect was predominant for the characters, plant height and oil content. The parents SKP-8, 103745, 1379, SKP-93, TMV-5, Aruna, SH-72 and SK2-8A were good general combinersfor imparting earliness, former three as well as VP-1 were good general combiner forshort plantstature. The parents SH-72, SK 2-BA, SKP-82,JH-128, SH-41 and 48-1 were good general combiners for oil content. The estimates of gca effects suggested that parents SKP-93, SKP-82, 48-1, Aruna, SPS-35-9B,JI-77 and JH-128 were good general combinersforseed yield and several yield components viz., 100 seed weight, effective branches/plant, number of capsulesin main raceme and length of main raceme. The good specific cross combinations for yield viz., SKP-8 x TMV-5, VP-l x SKI-41 and SKP 25 x 1379 were also identified as superior hybrids for earliness, high oil content and short plant stature, respectively and may be exploited for commercial cultivation. The hybrids SKP-8 x TMV-5, SKP-25 x JH- 128 and SKP-82 x 48-1 with significant positive sca effect for seed yield could be exploited for development of hybrids and new inbred as well as pistilate lines in castor. The potence ratio of genetic variance suggested preponderance of non-additive gene effect for inheritance of the seed yield/plant, number of capsules in main raceme and number of effective branches.

Diversity Analysis in Indian Mustard (Brassica juncea L. Czern &amp; Coss)

The present investigation was conducted with forty-six Indian mustard genotypes involving B. juncea x B. juncea and related species i.e. B. juncea x B. carinata, B. juncea x B. napus and somaclone background. These were evaluated to identify the genetically diverse genotypes for exploitation in a breeding programme aimed at improving yield potential of Indian mustard. Amongst seven clusters formed (Mahalanobis D2, 1936), each of the cluster I and IV had the largest genotypes (nine) and cluster II with smallest (two genotypes). Maximum divergence was observed between cluster V and VI followed by cluster V and VII and cluster II and VI. The genotypes RAURD-166, RAURD-205, RAURD-241, RAURD-32, JD-6, RAURD-168, RAURD-78, RAURD-195, RAURD-246, RAURD-172, RAURD-25 and RAURD-34 were observed as more divergent. Cluster V recorded minimum for plant height with early flowering and maturity, cluster VI, had more for primary branches per plant, secondary branches per plant, number of siliqua per plant, number of seeds per siliqua, biological yield per plant and seed yield per plant. The cluster VII had high mean for length of main raceme, siliqua on main raceme and seed yield per plant and cluster II, had high mean value for siliqua density. The clusters VI, VII, V and II were observed as more divergent clusters with high seed yield. The probability of getting better segregants and promising recombinants is expected to be more, from selecting genotypes of these clusters.

Correlation analysis in different planting dates of rapeseed varieties

The present study was aimed at finding out the planting dates effects on yield associated traits and also determining the variations of correlations among the traits in different planting dates of rapeseed genotypes. Significant planting dates and genotypes effects for phenological traits, yield components, seed yield and oil percentage revealed significant differences of planting dates and genotypes for these traits. Plant height had positive effect on pods per plant by increasing number of branches in each plant and length of main raceme. 1000-seed weight had significant positive correlation with seed yield, so any changes for this trait had considerable effect on seed yield. The variation of correlation between duration of flowering and pods per plant was less than the correlation of duration of flowering to other traits in different planting dates, so it can be used as selection breeding criterion. DOI: http://dx.doi.org/10.4038/jas.v7i2.4407 The Journal of Agricultural Sciences, 2012, vol.7, no 2 76-84

Influences of plant density on the seed yield and oil content of winter oilseed rape (Brassica napus L.)

A field experiment was conducted to investigate the influences of plant densities on the seed yield and oil content of the winter oilseed rape (Brassica napus L.), which included two varieties, Zhongshuang No. 11 (ZS) and Ganyouza No. 1 (GY), and three densities (2.4×104, 3.6×104 and 4.8×104planthm−2) treatments in two consecutive growing seasons (2009–2010 and 2010–2011). Results showed that, compared with 2.4×104planthm−2, the seed yield per plot of 3.6×104 and 4.8×104planthm−2 treatments were significantly increased in both growing seasons, which might be due to the raceme and pod numbers per unit area were significantly increased with the increase in plant densities. And the seed oil content was significantly increased with the increase in plant densities, which might be due to the proportion of seed yield of main raceme significantly increased. Meanwhile, the seed oil content and 1000 seed weight of main raceme were significant higher than branch raceme about 1.0% and 10.0%, respectively. And the influences of plant densities on the seed yield of winter oilseed rape are mainly on the branch raceme and less on the main raceme. These results indicated that increasing the main raceme numbers per unit area and the production capacity of main raceme might be an effective means to increase the seed yield and oil production of winter oilseed rape.

The Heterosis and Combining Ability of Diallel Crosses of Rapeseed Inbred Lines

The heterosis and combining ability of four rapeseed (Brassica napus L.) genotypes were estimated using diallel crosses. An experiment was conducted at Uludag University, Bursa, Turkey, during the 2005-2006 and 2006-2007 growing seasons using 4x4 full diallel crosses. All of the 12 F1 hybrids and their parents were planted in a randomized complete block design with three replications. The data obtained from the experiment were subjected to an analysis of variance. The analysis of variance indicated significant differences among parents and their hybrids in the F1 generation for all the characters studied except for 1000-seed weight, which was non-significant. Positive better-parent heterosis for seed yield per plant were found in all 12 hybrids tested. An analysis of the components of combining ability showed that general combining ability (GCA) and reciprocal combining ability (RCA) were highly significant (p ≤ 0.01) for plant height and number of pods per main raceme, whereas specific combining ability (SCA) was highly significant for all traits but 1000-seed weight. The parent genotypes PR1, PR3 and PR4 with the hybrids PR1 x PR3 and PR1 x PR4 showed higher GCA and SCA effects, respectively, and therefore could be used to develop high-yielding lines.

Relationship Among Yield Components and Selection Criteria for Yield Improvement in Early Rapeseed ( Brassica napus L.)

The objective of this study was to determine the relationship between seed yield and other important agronomic traits of early-maturing rapeseed as a rotation crop in a double-cropping rice area using Pearson's correlation coefficient as well as to estimate direct and indirect effects of specific yield component traits on seed yield via path analysis. Nineteen rapeseed genotypes were grown at ten environments in South China during 2008-2009 and 12 characters were evaluated. Analysis of variance showed that environment had a significant impact on all characters. For most characters the genotype by environment interaction was weak and not statistically significant. Simple correlation analysis indicated that the number of primary branches (PB), number of pods on the main raceme (PR), and number of seeds per pod made significant contributions to seed yield per plant (SYP), while 1 000-seed weight was negatively correlated with SYP ( r=−0.485, P<0.05). Furthermore, number of pods per plant (PP), PB, and PR had the greatest direct effects on SYP. In addition, PP and PB were the best indicators to predict seed yield in stepwise regression analysis. Finally, yield component differences between early- and medium-maturity varieties were compared; this showed that to improve the seed yield of early varieties, more emphasis should be given to increase PP, PB, and PR, and reduce plant height and shortening of growth duration in breeding practice.

Interrelationship between yield and yield related traits of spring canola (Brassica napus L.) genotypes

The research was conducted in order to determine yield related characters which are more effective as selection criteria than yield itself. Three spring canola (Brassica napus L.) genotypes have been investigated for plant height, number of primary branches (including the main raceme), number of pods per plant, pod length, number of seeds per pod, seed weight per pod and 1000 seed weight and their correlations with seed yield per plant. Seed yield had highest correlation with number of pods per plant (r= 0.935 and r= 0.973 in Skopje and Strumica, respectively), followed by seed weight per pod (r= 0.693 and r= 0.729) and 1000 seed weight (r= 0.627 and r= 0.680). Path coefficient analysis was used to identify the direct and indirect effect of studied characters on seed yield. Number of pods per plant (p=0.759 and p=0.877 for Skopje and Strumica, respectively) and seed weight per pod (p=0.216 and p=0.225) had the highest direct effect on seed yield in both locations followed by 1000 seed weight (p=0.056 and p=0.010). The coefficient of determination (R2) was 0.943.

Divergência genética entre acessos e cultivares de mamoneira por meio de estatística multivariada

O objetivo deste trabalho foi avaliar a divergência genética entre acessos e cultivares de mamoneira (Ricinus communis L.) e utilizá-la como critério na escolha de genitores que viabilizem, a partir de hibridações, a formação de populações segregantes. Os tratamentos foram representados pelos acessos BRA 4871, BRA 2968, BRA 5550 e BRA 7722 Papo-de-gia, e as cultivares BRS 188 Paraguaçu, BRS 149 Nordestina, IAC-80, Mirante-10 e Pernambucana Melhorada. As características analisadas foram: início do florescimento (FR), número de racemos por planta (NRP), comprimento efetivo do racemo primário (CR), altura de planta (AP), potencial produtivo (PP) e teor de óleo nas sementes (TO). A divergência genética foi estimada por meio de estatística multivariada, com base em variáveis canônicas e análise de agrupamento, tendo-se empregado a distância euclidiana média. Houve a formação de dois grupos: o grupo I formado por oito genótipos e o grupo II por apenas um genótipo, a cultivar Mirante-10. Apesar de a cultivar Mirante-10 ter sido a mais divergente, não deve ser recomendada para hibridação, por sua baixa média de desempenho. As demais cultivares também apresentam restrições para hibridação, por serem bastante similares. As variáveis que mais contribuíram para a divergência genética foram FR, AP, TO e CR.

Genetic analyses of agronomic and seed quality traits of synthetic oilseedBrassica napus produced from interspecific hybridization ofB. campestris andB. oleracea

The heritability, the number of segregating genes and the type of gene interaction of nine agronomic traits were analysed based on F2 populations of synthetic oilseed Brassica napus produced from interspecific hybridization of B. campestris and B. oleracea through ovary culture. The nine traits-plant height, stem width, number of branches, length of main raceme, number of pods per plant, number of seeds per pod, length of pod, seed weight per plant and 1000-seed weight-had heritabilities of 0.927, 0.215, 0.172, 0.381, 0.360, 0.972, 0.952, 0.516 and 0.987 respectively, while the mean numbers of controlling genes for these characters were 7.4, 10.4, 9.9, 12.9, 11.5, 21.7, 20.5, 19.8 and 6.4 respectively. According to estimated coefficients of skewness and kurtosis of the traits tested, no significant gene interaction was found for plant height, stem width, number of branches, length of main raceme, number of seeds per pod and 1000-seed weight. Seed yield per plant is an important target for oilseed production. In partial correlation analysis, number of pods per plant, number of seeds per pod and 1000-seed weight were positively correlated with seed yield per plant. On the other hand, length of pod was negatively correlated (r = -0.69) with seed yield per plant. Other agronomic characters had no significant correlation to seed yield per plant. In this experiment, the linear regressions of seed yield per plant and other agronomic traits were also analysed. The linear regression equation was y = 0.074x8 + 1.819x9 + 6.72x12- 60.78 (R2= 0.993), where x8, x9 and x12 represent number of pods per plant, number of seeds per pod and 1000-seed weight respectively. The experiment also showed that erucic acid and oil contents of seeds from F2 plants were lower than those of their maternal parents. However, glucosinolate content was higher than that of the maternal plants. As for protein content, similar results were found in the F2 plants and their maternal parents. It was shown that the four quality traits, i.e. erucic acid, glucosinolate, oil content, and protein content, had heritability values of 0.614, 0.405, 0.153 and 0.680 respectively.