After the crosses and seed multiplication of the parents, two field experiments were installed in the second season of 2015, the first in Maringá-PR (latitude 23º 25’ S; longitude 51º 57’ W); 550 m asl, and the second in Araruna - PR (latitu- de 23º 52’ S; longitude 52º 32’ W; 510 m asl). The soil at both sites is classified as Dystrophic Red Latosol. All cultural operations were performed according to official recommendations for second season maize (Cruz et al., 2006). The following traits were evaluated: a) grain yield (GR), kg ha -1 , b) mean plant height (PH) and insertion height of the highest ear in the stem (EI) in cm; c) silking (SIL), in days; d) final plant density (FD) and e) poppingexpansion (PE), calculated as the ratio between expanded popcorn volume and raw grain weight (in mL g -1 ).For each plot, a 30 g grain sample was popped in an electric popper, with automatic temperature control, set at 280ºC, developed by Embrapa-National Center for Research and Development of Agricultural and Livestock Instrumentation (CNPDIA). The expanded popcorn volume was measured in a 2,000 mL graduated beaker. The grains for popping were taken from the central basal part of the ears, with a moisture content between 12.5 and 13.5% (Luz et al., 2005).
ABSTRACT: Among the insects infecting the maize (Zea mays L.) crop in Brazil, the fallarmyworm (Spodoptera frugiperda Smith, 1797, Lepdoptera: Noctuidae) is considered one of the most important because it causes the highest damage toyield. Genetic resistanceto the fallarmyworm has be an effective control strategy. The main objective of this work was to evaluate new germplasm sources for resistanceto the fallarmyworm, the key pest for the maize crop in Brazil. A partial diallel design between 20 varieties of Brazilian germplasm and nine exotic and semi-exotic varieties of different origin was used. The 180 crosses and 29 parental varieties along with two commercial checks were evaluated in three locations in the State of São Paulo State (Brasil). Fallarmywormresistance (FAWR) under artificial and natural infestations, grain yield (GY), and plant height (PH) were analyzed. The populations CMS14C and MIRT, and hybrid São José x MIRT showed the highest resistance, with values of 1.8, 1.7 and 1.4, respectively. Populations PMI9401 and PR91B, and the hybrid CMS14C x (B97xITU) had best yields, with 4893, 3858 and 5677 kg ha -1 , respectively. Heterosis ranged from
Abstract: To date, no studies on the inheritance of Fusarium spp. ear rot resist- ance in popcorn are available. The purpose of this paper was to investigate the additive-dominance model to estimate the genetic components of variance, heritability and the inheritance pattern in a diallel for popcorn, by Hayman’s approach. The experiment was carried out in two environments, using eight parent lines. The following traits were measured: grain yield (GY), poppingexpansion (PE), incidence of ears infected by Fusarium (FusIE), total number of kernels infected by fungi (FunIK) and total number of kernels infected by Fusarium spp. (FusIK). The results indicated that the incidence of FusIK (Fusarium-infected kernels), FunIK (fungus-infected kernels), and FusIE (Fusarium-infected ears) is controlled by dominant genes. Parent L77 had a high number of favorable alleles for all resistance-related traits, as well as for PE. The strategy recommended for reduction of FunIK, FusIK, and FusIE consists of exploiting hetorosis using inbred lines with favorable alleles.
Multivariate analysis might be a suitable approach to analyse data ofresistanceto FAW in maize. In fact, different statistical procedures have been used in modeling morpho-physiological andyield traits, as well as plant disease resistance, including principal component analysisand factor analysis (Aaliya et al. 2016), and also other multivariate procedures (Veturi et al. 2012; Wisser et al. 2011). The principal component analysis is a multivariate statistical method, which reduce the dimension of multivariate data by removing inter-correlation among variables. Each principal component is a linear combination of the original variables that represent a multidimensional relationship plotted on two or three principal axes (Hayman 1967). Factor analysis aims to explain observed relations among numerous variables by removing redundancy or duplication traits from a set of correlated phenotypic variables (Cattell 1965). These statistical methods can easily select important traits and reduce the data size to explore the relationships between traits, their variations and also show their relationships with the environmental factors (Vile et al. 2012).
The southern rust is caused by Puccinia polysora Underw., and well-adapted to high and low lands in Brazil, and other tropical and sub-tropical environments where maize grown (SHURTLEFF, 1992). This rust has affect leaves causing yield losses up to 50% (CASTELLANOS et al. 1998; RODRIGUES-ARNON et al., 1980). The partial resistanceto southern rust, or slow-rusting, consists of the ability to decrease the disease rates of development, usually by small lesions and less sporulation (ZUMMO, 1988). Since the area under the disease progress curve (AUDPC) measures the disease development over a period, this criteria is commonly to assess partial resistance levels under field conditions.
Fifty-six hybrids (F1’s, reciprocals and parents) were obtained for composition of a complete diallel including eight parents: ‘Maradol’, ‘JS 12-N’, ‘JS 12-4’ and ‘Sekati’ - ‘Formosa’ group; and, ‘Waimanalo’, ‘Golden’, ‘Sunrise Solo 72-12’ and ‘São Mateus’ - ‘Solo’ group. The experiment was established at the Farm Romana of the Company Caliman Agrícola S/A, in Linhares, Espírito Santo State. The parents were chosen on the basis of prior information obtained in topcross studies (Ide et al., 2009; Vivas et al., 2011, 2012a), partial diallel (Marin et al., 2006a, b) and genetic diversity (Quintal et al., 2012). We sought to use in the diallel crosses, parents that demonstrated to have good qualitative and quantitative agronomic traits, not only in terms per se, but also in terms of breeding values.
T. remus development time required from egg to adult is reduced by an increase in temperature due to an increase in metabolic activity of the parasitoids (HERNÁNDEZ & DIÁZ, 1996). This reduction occurs until a superior limit of temperature that allows the insect survival. Our results on development time (egg to adult) are similar to the ones reported by GERLING (1972) who studied this biological parameter just at temperatures of 22 and 25°C. Other species of Telenomus might require different time to develop from egg to adult (GERLING, 1972; HERNÁNDEZ & DIÁZ, 1996). Therefore, this biological parameter relies on temperature as well as insect race adaptation. It was verified for Trichogramma pretiosum (PRATISSOLI & PARRA, 2000).
ABSTRACT. The development of melon lines resistant to gummy stem blight (GSB) is an important strategy for decreasing losses caused by this disease. Thus, selecting the best parents for such a goal is essential. We evaluated the general (GCA) and specific (SCA) combining abilities of lines and accessions to guide the selection of the most promising parents to develop GSB-resistant lines. Six genotypes representing two groups (group I - susceptible: group II - resistant) were crossed in a partial diallel mating design. The genotypes were evaluated for disease expression using a rating scale from 0 (resistant) to 4 (susceptible). Estimates of GCA were negative and significant for the accessions PI 420145 and PI 482398, which can be suggested for crosses aimed at obtaining melon lines resistant to GSB. There is a reciprocal effect for the resistanceof melon genotypes to Didymella bryoniae, especially when PI 482398, PI 420145, and PI 140471 are crossed with JAB-20. Such results indicate that maternal effects may be involved in the resistanceto gummy stem blight.
So, with this experiment we could identify genotypes (lines andpopulations) of tomato plants with good resistance levels to T. absoluta, mediated by exudates from allelochemicals. Lima et al. (2015) found that the selection for high zingiberene content is an efficient way to obtain plants presenting resistanceto the tomato leafminer. Lucini et al. (2015) also studied the resistance mechanisms presented by F 2 genotypes with contrasting acylsugar contents from a crossing between S. lycopersicum and S. pennellii accession ‘LA-716’. By means of choice and no- choice tests, the presence ofresistance mechanisms by antixenosis and antibiosis in F 2 genotypes selected for high acylsugar contents, was identified when submitted to the presence of the tomato leafminer. All these studies confirm the efficiency of the selection through the allelochemicals levels. The genotypes obtained in this study have fruits with a shape for the referring groups Santa Cruz, Saladette, Italian, and multilocular, in addition to some fruits with an intermediate shape. This way we could relate resistance with specific fruit shape that the consumer market requires.
The theory of variance analysisof partial diallel tables, following Hayman’s proposal of 1954, is presented. As several statistical tests yield similar inferences, the present analysis mainly proposes to assess genetic variability in two groups of parents andto study specific, varietal and mean heteroses. Testing the nullity of specific heteroses equals testing absence of dominance. Testing equality of varietal heteroses of the parents of a group is equivalent to testing the hypothesis that in the other group allelic genes have the same frequency. Rejection of the hypothesis that the mean heterosis is null indicates dominance. The information obtained complements that provided by diallelanalysis involving parents and their F 1 hybrids or F 2 generations. An example with the common bean is included.
The calculated heritabilities for grain yield indicated that broad sense was high in each environment and intermediate in the ratio, while narrow sense was low except in the low-Al environment. High broad sense heritabilities were found for K, Al, Fe and Zn; for Ca, Mg and Cu, they had intermediate values; the genetic differences for Mn seemed rather complex. Narrow sense heritabilities were of low values for all elements. Similar results were obtained for mineral element uptake in maize, forage sorghum and soybeans (Gorsline et al., 1968; Gorz et al., 1987; Spehar, 1995a). The lack of fitness of the additive-dominance model may have been a consequence of possible residual heterozigosity in the parental cultivars. Indication of genetic variability for low-Ca tolerance within soybean cultivars has already been reported (Spehar & Galwey, 1997). However, despite the limiting factors, these results suggest that soybeans can be improved for high yieldand tolerance to Al by using modified pedigree, early generation testing on hill plot and recurrent selection, following hybridisation of superior individuals (Spehar, 1994b).
The sclerotia can germinate in two ways, myceliogenic or carpogenic. Myceliogenic germination is characterized by the growth of hyaline, septate, multinucleated and branched hyphae, formed from sclerotium micropores. Carpogenic germination is considered the main cause of epidemics in the field . This germination begins with the growth of fungal cells, called stipes. These in turn, when exposed to the light, differ in apothecias that release thousands of ascospores responsible for initiating the disease in the aerial part of the plant.
The purpose ofdiallel analyses is to assess the genetic design, estimating useful parameters in the selection of parents for crosses, and explain the genetic effects involved in determining their characteristics. The most commonly used method is the one proposed by Griffing (1956), which estimates the general combining ability (GCA) and specific combining ability (SCA) of the genotypes from diallel crosses. The first measures the relative performance of a lineage in a series of crosses and is associated with additive genetic effects; and the second characterizes the performance of specific hybrid combinations in relation to the average of their parents and is related to the effects of dominance, epistasis and various types of allelic interactions (CRUZ; REGAZZI; CARNEIRO, 2012).
ABSTRACT: Fallarmyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) is one of the main pests in maize crop with developing resistanceto chemical products and Bt technology. Therefore, alternative control methods such as essential oils are important steps in the implementation management strategies for this pest. This study aimed to evaluate the efficiency of essential oils (EOs) of Corymbia citriodora, Myrciaria dubia (Myrtaceae), Lippia microphylla (Verbenaceae) and Piper umbelattum (Piperaceae) in controlling S. frugiperda. The OEs were extracted and mortality tests were conducted with topic and volatile applications, in 30 second-instar caterpillars originated from insect rearing and artificial diet. As a control, we conducted tests with distilled water and acetone. EOs that provided mortality rates above 80% were submitted to chemical analysis for constituent identification. The efficient EOs were only those of C. citriodora and L. microphylla. For EO of C. citriodora, the LD80 was 7.06 ± 0.73 mg.g -1 in topical application and 5.85 ± 0.75 μL via volatile application. On the other hand, for EO of L. microphylla, DL80 was 9.95 ± 1.25 mg.g -1 in topical application and 18.56 ± 3.55 μL via volatile application. Chemical analysis showed that the main constituents were citronella for the EO of C. citriodora and (E)-caryophyllene and (E)-nerolidol to the EO of L. microphylla. EOs of C. citriodora and L. microphylla are promising for controlling S. frugiperda, with emphasis on the volatile effect of C. citriodora oil.
As proposed by Fan et al. (2014), considering the impact of reciprocal crosses on GY and SCA estimation, the possible result would have a great impact on maize heterotic group classification. Another study recently reported how MAT influenced GCA effects and how REC affected SCA effects in Griffing’s Method 1 and 3 (Mahgoub 2011). The current proposed model should be relevant to analyze a partial diallel mating design, using key genetic statistics that allow the computation of REC as well as maternal (MAT) and cytoplasmic effects (CIT). None of the above studies reported the impact of reciprocal crosses or REC on a partial diallel mating design.
para todo j, do modelo de Gardner & Eberhart não satisfazem os valores paramétricos dos efeitos de heterose específica; em conseqüência, os estimadores dos efeitos de heterose de população, dos efeitos de heterose específica e de suas variâncias diferem daqueles do modelo irrestrito; as análises considerando os modelos irrestrito e de Gardner & Eberhart devem conduzir às mesmas inferências, pelo menos em relação às decorrentes da avaliação dos efeitos de população expressos como desvios em torno do efeito médio, das heteroses, da heterose média e das heteroses varietais (a correlação entre as estimativas dos dois modelos é 1); o fator que limita o uso do modelo irrestrito é a inexistência de fórmulas para o cálculo das somas de quadrados e Table VI - Estimates of the heteroses (H jj’ ; values below the diagonal),
ABSTRACT. The aim of this study was to evaluate a diallelof maize hybrids for traits related to forage production and nutritional value. Six commercial hybrids were used as parents. The crosses were made according to a complete diallel design, obtaining the F1 and reciprocal crosses. The evaluations were performed in the main and second crop seasons in the 2010/2011 crop year at the Center for Technological Development in Agriculture of the Federal University of Lavras, located in Lavras, Minas Gerais State, Brazil. The experimental precision indicated by the coefficient of variation was good for all the traits measured. Significant differences were not observed among the crosses for traits related to the nutritional value of the forage. For fresh matter yieldand dehusked ear yield, the general combining ability (GCA) and specific combining ability (SCA) effects were significant. Sowing in the second crop season reduced the yieldand nutritional value of the forage. The interaction among the crosses and sowing seasons was not significant. For the beginning of an intrapopulational breeding program, the parent BM 3061 stands out by showing high estimates of GCA for the grain and forage yields.
Plant height is an important trait in the choice of the most appropriate spatial arrangement for planting, since Jatropha can exceed 5 m height. Thus, the breeder’s efforts focus on selecting plants with small size for easier harvesting. Therefore, the selfings 107x107 and 190x190 were the most promising for PH reduction. Moreover, the hybrid formed by crossing the parents 107 and 190 and the selfings presented high mean for GY by the Scott-Knott test; thus, they formed the cluster with high GY (Table 4). Teodoro et al. (2016) observed that PH presents negative cause-effect relation with GY, suggesting that self-pollination of these genotypes may have contributed to the increase in the frequency of favorable alleles for the increment of GY andto the reduction of the size.
ABSTRACT - The aim of this study was to quantify and assess the components of heterosis in paprika hybrids related toyield, capsanten pigment content (estimated as ASTA degrees) andresistanceto Phytophthora capsici, andto identify parental lines with high general combining ability (GCA) to be used in future breeding programmes and/or to obtain new hybrids. Fifteen hybrids were obtained through a complete diallel cross (reciprocal hybrids excluded) among six proprietary paprika breeding lines from HortiAgro Sementes S.A., four of which originally introduced from Peru (P 1 =PIM 032-03; P 2 =PIM 033-11; P 3 =PIM 034-19; P 4 =PIM 035-01) and two from the U.S.A. (P 5 =PIM 036-08; P 6 =PIM 037-18). Epistatic gene action was involved in the expression of heterosis for fresh and dry yields and carotenoid pigment contents, and heterosis was predominantly in the direction of higher yields. No significant heterosis effects were detected for resistanceto P. capsici, and gene action was of incomplete dominance for the resistant phenotype. The parental lines P 1 and P 5 showed high GCA values for all characters, and may be used in breeding programmes to obtain new improved lines or for the production of higher yielding hybrids. The most promising hybrid was P 3 xP 5, which outperformed the standard cultivar “Papri Queen” in fresh (68 t ha -1 ) and dry (10 t ha -1 ) fruit
Partial diallel cross provides estimates of GCA and SCA for a specific set of lines, and this analysis has been used to evaluate the combining ability and performance of several maize lines with respect to many traits (Henry et al. 2014). The present results, which evaluated the cross between temperate × tropical materials, were significant for GCA and SCA effects, suggesting additive gene action in the control of the traits SY, PH, EH, PM and ET. The percentages of contribution of the GCA effect were higher than that of the SCA effect for all the five traits evaluated. PH, EH, GY, PM and ET showed 96.17%, 92.86%, 91.96%, 94.04% and 87.79% of the contribution of the GCA effects, respectively, indicating the importance of additive gene action and high frequency of favorable alleles controlling the five traits studied (Table 2). Studies that aimed at investigating the combining ability in tropical and temperate maize lines were significant for GCA and SCA for the agronomic traits of interest, such as grain yieldand plant height (Henry et al. 2014, Werle et al. 2014). Specifically, Henry et al. (2014) showed that the additive effects were more important than the non-additive effects for PH, confirming the present results. Similarly, for P. maydis and E. turcicum, some studies have demonstrated the importance of additive effects controlling these traits (Vivek et al. 2010). Conversely, for SY, contrasting results have been reported, revealing the importance of additive and non-additive effects controlling this trait (Henry et al. 2014, Werle et al. 2014). Given the importance of GCA in all traits, exotic, previously protected temperate maize germplasm may provide novel alleles for resistanceto P. maydis and E. turcicum, which have not been observed in tropical maize materials. Similarly, to improve agronomic important traits, this germplasm may serve as a source of new alleles to increase yieldand stabilize production.