Inbreeding depression in castor bean (Ricinus communis L.) progenies

Cropp Breeding and Applied Biotechnology, 2004

RAPD markers were used to assess the potential five inbreeding methods have to release genetic variability. These methods were employed until family selection in the F 5 generation, plus the parents Carioca and Flor de Mayo, and the test cultivar Pérola. DNA was extracted from 16 plants per family for RAPD reaction. Twenty-two primers amplified DNA fragments linked to a number of grain yield loci, weight of 100 seeds, number of days to flowering, and reaction to the oidium and angular leaf spot. To estimate genetic similarities between every genotype pair in each inbreeding method 42 polymorphic bands amplified among the families and parents were used. Genetic similarities were UPGMA-clustered and grouped by multidimensional scaling. The bulk method was most efficient to release genetic variability, followed by bulk in F 2 families, SSD, bulk in F 3 families, and pedigree. The bulk method created families with higher similarities close to the Carioca, which is one of the regionally most grown cultivars.

Euphytica, 1999

The germplasm of cultivated common bean exhibits a lower level of genetic diversity within each geographical gene pools (Mesoamerican and Andean) compared to that of the respective wild ancestors. Crosses between these two gene pools potentially provide a source of additional genetic diversity but their progenies have been characterized by phenotypic abnormalities and reduced productivity. In order to gain additional insights into this problem, we examined the segregation for performance in two recombinant inbred populations (RIPs) resulting from Mesoamerican × Andean crosses in three contrasting environments and two years. The two RIPs – ‘California Dark Red Kidney’ (of Andean origin) × ‘Yolano’ (Mesoamerican), n = 150, and A55 (Mesoamerican) × G122 (Andean), n = 67 – were grown in replicated field tests to assess the agronomic performance of each recombinant inbred line. Both populations exhibited, on average, greater days to maturity (DTM), lower biomass growth rate (above-ground dry weight/DTM), lower economic growth rate (seed yield/DTM), and lesser harvest index. In contrast with the conclusions of earlier experiments, there was no evidence from the field trials for a genetic association (due to linkage or pleiotropy) between seed weight and economic growth rate, but there may be a genetic association between seed weight and life cycle length. We compare the results of these studies with earlier experiments on inter-gene pool recombinant populations of common beans and relate our observations of diminished performance to models of speciation mechanisms.

2007

S-45 ommon bean (Phaseolus vulgaris L.) is the most widely consumed grain legume in the world. This cultigen was domesticated from wild P. vulgaris, an indeterminate viny plant, distributed from Mexico to Argentina in midaltitude neotropical and subtropical regions. To colonize such diverse ecological niches, the species possesses many adaptation traits and a wealth of genetic diversity. However, breeding programs are limited by the under-utilization of the available genetic diversity because of the necessity of prebreeding exotic material. Due to partial reproductive isolation between the domesticated Andean and Mesoamerican gene pools, hybridizations between wild and domesticated types of P. vulgaris from the same gene pool offer greater potential to enhance the variation in the crop. Evaluations of wild P. vulgaris accessions have shown resistance to insects and diseases and higher N, Fe, and Ca content in seeds, which will ultimately contribute to improvements in nutritional quality and yield. Recurrent and inbred backcross methods are being used for the transfer of both qualitative and quantitative traits from wild into domesticated forms of P. vulgaris; specifi c data on yield and 100-seed weight are presented. The prebreeding efforts will be enhanced by (i) information on gene pool origins, domestication syndrome traits, molecular diversity, and mapping data of the wild forms; (ii) indirect screening for biotic and abiotic stresses; and (iii) marker-assisted selection.

The phenotypic stability of nine recombinant inbreed lines of French bean were tested for growth and yield components by growing them in four different environments. Results revealed highly significant difference among the genotypes for all the traits studied except for pod weight, days to 50 percent flowering and days to maturity. Significant variation among the environments was observed for almost all the characters studied except for pod weight and days to maturity. Genotype x environmental interaction were significant for pod length, pod weight and green pod yield per plant, which indicates differential performance of genotypes under different environments. Among the recombinant inbreed lines tested for stability, inbreed line, 6-1 had maximum green pod yield per plant and is most stable over different environments with high mean values, regression coefficient around unity and non-significant deviation from regression.

Field Crops Research, 2009

Due to adaptation to new ecological and manmade conditions, the large diversity evolved in the European common bean germplasm is of particular interest for plant breeding. The knowledge of the genetic relationships within and among races and gene pools and their performance per se will provide bean breeders with a starting point in designing crosses using contrasting and complementary parents to broaden the genetic base within the different commercial classes. A genetic study of seed size variation and protein markers in progeny derived from 16 intraracial, interracial and inter gene pools European common bean populations was conducted. General and specific combining ability (GCA and SCA) values were significant for seed weight, indicating that both additive and nonadditive genetic effects were involved in conditioning seed weight. Interracial populations showed transgressive values due to the accumulation of large-seeded alleles. Genetic variation inside Andean germplasm, and Chile and Peru races in particular, exhibited useful genetic progress in these populations, providing lines with a large seed size, and so, an excellent market potential. The distribution of incompatibility between both gene pools (Mesoamerican and Andean) of the common bean was explored. Inter-gene pool populations provided lower means of inbred segregants than the mid-parent value. Therefore, a good option it would be select for large seed size according to a recurrent or congruity inbred-backcrossing selection programs. Analysis of allele markers frequencies in inter gene populations showed segregation distortion with a higher than expected frequency of alleles from the Mesoamerican gene pool, many of which were fixed in the F 7 lines. The presence of a great percentage of markers that showed segregation distortion in these populations (87 %) indicated that this phenomenon can be amplified by using distance related common bean genotypes. In addition, a high percentage of heterozygotes for the Phs locus (for the seed storage protein phaseolin) was found, which suggest that the Andean homozygous TT could not be expressed in Mesoamerican genetic background due to the action of some form of female specific mechanisms that affected gene exchange between parental germplasm in inter-gene pool populations. The present work provides useful information in the establishment of large seed size germplasm that could have a great deal of interest among breeders and may offer some possibilities to exploit existing variation within and between common bean races.

Bulgarian Journal of Agricultural Science

The castor bean (Ricinus communis L.) cultivation emerges as a promising activity for biodiesel production. There is limited information on genetics of modern castor bean cultivars. To be able to foresee results of selection for a characteristic in a population, it is necessary to determine the values of genetic variance, environmental variance and their interaction within the total phenotypic variance. Castor bean studies have mostly been concentrated on the roles of additive and dominant gene effects in the expression of quantitative characteristics. Two two-line castor bean hybrids have been evaluated for mode of inheritance and gene action in the expression, especially epistatic one, of the number of flowers, number of filled seeds per flower head and 1000-seed mass. Epistatic gene effects have played important roles in the inheritance of the studied characteristics in both hybrids. Highly significant values of epistatic gene effects additive × additive and dominant × dominant h...

This investigation was carried out in four winter seasons: 2017-18 (F2), 2018-19 (F3), 2019-20 (F4), and 2020-21 (F5) at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate, Egypt, to study the comparison between three breeding methods: pedigree, bulk, and single pod descent for improving seed yield in segregating generations of faba bean crosses: (1) Triple White x Giza 429; (2) Ohishima-Zaira x Giza 429; (3) Giza 40 x Giza 429; and (4) Ohishima-Zaira x Foul Sbai labiade. The pedigree method had a superiority over the other two breeding methods for almost all studied traits in all crosses of the three generations, except for the cross 1 of the F4 generation and the cross 4 of the F5 generation, where the bulk method had a superiority. Narrow-sense heritability estimates were moderate in the four studied crosses of the three generations, with few exceptions. Predicted genetic advance estimates were moderate for the number of branches, pods, seeds, and seed yield per plant in all crosses of the three generations. While the same estimate was low for chocolate spot disease, flowering date, plant height and 100-seed weight in approximately all crosses of the three generations. Comparable predicted genetic advances were observed with respect to the two breeding methods for chocolate spot disease in F3 and F4 generations. while bulk exceeded that for single pod descent in the F5 generation. The bulk method had a superiority over single-pod descent in the three generations for the number of pods and seeds per plant. The bulk method exceeded that for single pod descent in the F5 generation for seed yield per plant. Broad-sense heritability was moderate under bulk as well as single pod descent methods for plant height, number of branches, pods, and seeds per plant, and seed yield per plant. Predicted genetic advance was considered moderate in most cases, except for chocolate spot disease in the cross 3 and 4 of all generations, rust disease in the cross 3 of F3 and F4-generations, and flowering date in all crosses of all generations where the values were considered low.

The testcross method is considered efficient for identifying inbred families with superior general combining ability. The objective of the present study was to assess the relative importance of the performance per se and in crossing in the selection of inbred progenies using bi-trait best linear unbiased prediction. We analysed data for expansion volume (EV) and grain yield from three tests of popcorn (Zea mays L. ssp. everta) S 3 families and seven testcross trials, using the ASRemL software. Four selection strategies were assessed based on: breeding value (strategy 1), general combining ability effect (GCA) (strategy 2), additive value and GCA from strategies 1 and 2 (strategy 3), and breeding value and GCA predicted by bi-trait analyses considering EV and yield of the families and testcrosses as different traits (strategy 4). The bi-trait analyses of the same characteristic assessed in S 3 families and topcrosses were generally more accurate and had greater heritabilites. The greatest predicted gains in EV were obtained using strategy 4, which was inferior to the other strategies for the yield predicted gains. Strategies 1 and 2 differed most for the families selected. Selection based on GCA maximised heterosis. All of the strategies resulted in comparable realised gains, especially the strategies 3 and 4 based on breeding value and GCA. Selection on S 3 based on the additive value and GCA (strategies 3 and 4) resulted in inbred lines superior in number of favourable genes and in general combining ability.

Genetics and Molecular Biology, 2004

A segregant bulk population derived from a single cross between the Carioca MG cultivar and the ESAL 686 line was used to investigate whether the action of natural selection in the direction required by the breeders and the delaying line extraction would increase the chance of obtaining families with greater grain yield. The populations were advanced from F 2 to F 24 and obtained families F 2 , F 8 and F 24 from the plants. These families and their parents were assessed for grain yield (kg/ha) in Lavras-MG in three sowing seasons (July 2001, November 2001 and March 2002) in an 18 x 18 lattice design with two replications in the first sowing and three in the other two. The largest mean yield, regardless of sowing season, was among the families derived from the F 24 plants. The frequency of superior families increased when line extraction was delayed to more advanced generations.

Journal of Advanced Research, 2014

Five faba bean genotypes (Vicia faba L.) were selfed for two cycles to produce S1 and S2 generations. A half-diallel cross was carried out among them in each level of inbreeding (S0, S1 and S2) to obtain 10 F1 hybrids. Parental materials as well as their respective F1s were evaluated during the winter season of 2012. All studied traits except total dry seed yield showed significant inbreeding depression after the first generation of selfing (S1). No further decrease was noticed at the S2 generation. In the S1 generation the degree of inbreeding depression was highest for No. of branches/plant (-14.0%) and the least for weight of 100-seeds (-2.7). Some parents showed inbreeding vigor i.e. positive difference between S2 and S1 for some traits in S2 generation. Most studied traits showed significant positive heterosis values over mid-parent. The highest value of heterosis over the mid-parent was detected for total dry seed yield (128.8) and the lowest value of hybrid vigor was shown by weight of 100-seeds (1.2%). Specific combination among the 5 parental genotypes showed the highest value for heterosis for example cross Misr 2 × Giza 429 was the best cross for total dry seed yield, cross Giza 429 × Misr 1 for No. of branches/plant. Giza 429 is the best general combiner for most traits. Some crosses showed heterosis depression i.e. negative heterosis value in some traits. Hybridization among parental genotypes is recommended to be at the S1 or S2 generation. Twelve arbitrary primers produced different degrees of genetic polymorphism among the parental genotypes. A total of 65 amplification products were scored polymorphic. The percentage of polymorphic bands detected ranged from 33% to 100% with an average of 66.47%. The average of amplified bands was 5.42 polymorphic bands per primer. A positive, but non-significant, correlation (r = 0.085) between Euclidean distance and RAPD distance was observed.

East African Journal of Agriculture and Biotechnology

The objective of this work was to evaluate the genetic divergence between common bean strains from the breeding program of the Agricultural Research Institute of Mozambique (IIAM)-Zonal Centre (CZC) and to identify potential genitors to generate segregating populations with high average and wide genetic variability. Five common bean lines were evaluated in a randomized block design with three repetitions. The quantitative traits evaluated were leaf area index, days to 50% flowering, days to maturity, several pods per plant, 100 seed weight, and yield, while the qualitative traits were growth habit, epicotyl colour, leaf colour intensity, leaf roughness, fresh pod colour, grain colour, grain size, and flower colour. The data obtained were submitted to variance analysis and grouping of means by the Scott-Knott test. The relative importance of characters was evaluated by the Singh. Clustering was performed by the Tocher optimization method and distance projection in the 2D plane, using...

rdoapp.psu.ac.th

This research was conducted to determine inbreeding depression in S 1 maize lines for reproductive and yield related traits, at NWFP Agricultural University, Peshawar, Pakistan, in two successive seasons during 2002. Maize variety"Pahari" was selfed for one generation and 63 S 1 lines were evaluated using "lattice square design" with two replications along with the parental population. Days to mid silking and mid pollen shed (anthesis), plant height and ear height (cm), and 200 grain weight (g) showed inbreeding depression with varying degrees. Severe inbreeding depression was observed for yield with the average of 709 kg ha -1 . Inbreeding depression for 200 grains weight averaged 19 g, while for plant height and ear height it was calculated as 33 and 16 cm. Inbreeding depression for days to mid silking and pollen shed was lower as compared to morphological and yield components. Silking and pollen shed were delayed by 1.8 and 1.5 days on the average, respectively, as compared to the parental variety. Yield was significantly correlated with all maturity and morphological characters. Maturity characters were positively and significantly correlated with each other, showing good synchronization in maturity characters, while they were negatively and significantly correlated with yield components.

Botanical Sciences

Background and hypothesis: Castor bean (Ricinus communis) is spontaneous in Tunisia with a wide geographical distribution. To study seed morphology we introduced J index as the percent of similarity of seed images to an ovoid. Reduced seed size, J index and color intensity were observed in the population grown in the desert . Our objective is to analyze the variability in castor bean grown from seeds obtained from different geographic origins, to describe morphotypes and to find phenotypic parameters to select productive populations. Data description, mathematical model, study site and methods: Seeds collected from twelve populations in 12 Tunisian sites (4 bioclimatic regions) were sown in the experimental field of INRGREF in Gabes (Tunisia). After 10 months, morphological and agronomic characteristics of plants were measured. Morphological traits of seeds were analyzed. Results: Three groups were obtained. The first represented by a single population (northern Tunisia) is characterized by small leaves, large fruit, small seed and early flowering. The second group includes nine populations with intermediate values for fruit and seed dimensions. The third group characterized by reduced fruit length and elevated values of seed length and width. Seed yield varied between populations. Conclusions: Some features of seeds were maintained from the parental generation. Reduced size and color intensity with increased roundness values were maintained in the seeds of the Saharan region. J index values, reflecting the morphological similarity with an ovoid, increased in relation to the previous generation, in general as in particular in the seeds of the Saharan region.

2015

This study was carried out during 2011/12, 2012/13 and 2013/14 growing seasons. A diallel crossexcluding reciprocals among six parents of faba bean was utilized to broaden genetic base, to study heterotic and inbreeding effects, in addition to general, specific combining ability (GCA and SCA) and correlations among characters. Parents belonged to ssp Paucijuga and minor, equina and major types of ssp eu-faba. Results showed significant differences between parents, F1's and F2's for all studied traits indicating genetic diversity of parents. Significant heterosis relative to better parent (plus or minus values) occurred in 10 hybrids (out of 15) in days to 50 % flowering, 6 hybrids in plant height, 14 hybrids in branches per plant, 9 hybrids in pods per plant, 9 hybrids in seeds per plant, 12 hybrids in seed yield per plant and 11 hybrids in seed index. Heterosis relative to mid parents was significant in different hybrids in all traits. Inbreeding effects in F2 (depression o...