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Volume 5 Number 1 2011
CONTENTS AND ABSTRACTS
C. Indu Rani, D. Veeraragavathatham (India) Combining Ability and Gene Action for Yield and Processing Qualities in F1 Tomato (Lycopersicon esculentum Mill.) Hybrids (pp 1-9)
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ABSTRACT
Original Research Paper: Investigations were undertaken to study the combining ability and gene action for yield and processing qualities in F1 hybrids of tomato (Lycopersicon esculentum Mill.) by studying 80 hybrids that were developed, involving 14 parents mated in a line × tester fashion (both direct and reciprocal crosses). Among the parents, PT 4716A was judged as the best general combiner for the characters viz., plant height and number of fruits/plant and SL 120 was judged as the best general combiner for fruit weight and yield. The hybrids CLN 2026C × SL120, CLN 2026E × SL 120, LE 812 × SL 120 and CLN 1464A × SL 120 were judged as being the best specific combiners for yield and processing qualities. SCA variance was higher than GCA variance for all the characters indicating a better role of the non-additive type of gene action, thus emphasizing the importance of heterosis breeding to improve all characters studied.
Ali Qaid Ahmed Yahya Algabal, Narayanaswamy Papanna (India), Luke Simon (India/UK) Estimation of Genetic Variability in Tamarind (Tamarindus indica L.) using RAPD Markers (pp 10-16)
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ABSTRACT
Original Research Paper: In this study, genetic diversity among 36 genotypes of tamarind (Tamarindus indica L.) was analysed using RAPD markers. PCR-amplifiable DNA was isolated using the CTAB method and 106 amplified fragments were obtained using 12 random primers. The genetic dissimilarity matrix, which was calculated based on Squared Euclidian Distances, revealed a maximum genetic distance of 9.6% between genotypes, ‘NCBS1’ and ‘NB1’, and ‘PG2’ and ‘NB1’; the minimum genetic distance (4.2%) was between genotypes ‘NCBS2’ and ‘NCBS3’. The Ward’s method of cluster analysis grouped all the individuals on a dendrogram into two major clusters ‘A’ and ‘B’ at 19.5 linkage distance with two sub-clusters in cluster ‘A’. Sub-cluster ‘A1’ consisted of 7 genotypes and sub-cluster ‘A2’ 9 linked together at 12 linkage distances. Cluster ‘A’ predominantly consisted of genotypes with semi-curved to curved shape fruits and a characteristic plagiotropic tree growth pattern in sub-cluster ‘A1’ and orthotropic tree growth pattern in sub-cluster ‘A2’. Cluster ‘B’ consisted of two sub-clusters ‘B1’ and ‘B2’, clustered at 14.5 linkage distances with 7 and 13 genotypes, respectively. The genotypes of cluster ‘B’ was predominantly characterised by brown to dark brown coloured fruit pulp and the sub-clusters ‘B1’ with straight fruits and ‘B2’ with semi-curved to curved fruits. RAPD analysis proved to be a quick and simple testing method and resulted in a moderate level of genetic diversity among tamarind genotypes.
Ferjaoui Sahbi, Sbei Abdenour, Aouadi Nawel, Hamza Sonia (Tunisia) Monogenic Inheritance of Resistance to Septoria Tritici Blotch in Durum Wheat ‘Agili’ (pp 17-20)
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ABSTRACT
Original Research Paper: Full resistance to Septoria tritici blotch caused by the fungus Mycosphaerella graminicola and its genetic inheritance has rarely been described in durum wheat. A high level resistance to a virulent Tunisian isolate ‘Tun6’ has been detected in an old local durum wheat cultivar ‘Agili’. High yielding but susceptible durum wheat cultivars. ‘Karim’ and ‘Khiar’ were crossed with the resistant ‘Agili’. In both F2 populations, a 3: 1 (resistant: susceptible) segregation was observed after inoculation in the field with the isolate ‘Tun6’ at the seedling and adult stages, indicating that resistance is controlled by a single dominant gene. This genetic analysis was confirmed by F2-derived F3 families segregation of 1: 2: 1 (homozygous resistant: segregating: homozygous susceptible) ratio. Genetic analysis results are consistent with a single gene segregation indicating that there is a gene-for-gene interaction in the wheat-M. graminicola pathosystem and provides evidence that a qualitative resistance to Septoria tritici blotch exists in durum wheat.
Mohammad M. Ajlouni, Abdul Latief A. Al-Ghzawi, Hani Z. Ghosheh (Jordan) Inheritance of Grain Filling Rate and Duration, and Yield Components in Five Durum Wheat Crosses (pp 21-24)
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ABSTRACT
Original Research Paper: To understand the inheritance mechanisms of grain filling rate (GFR), grain filling duration (GFD), yield and yield components, twenty durum wheat landraces were selected from a larger set (~200 accessions) based on their yield and grain filling rate and all reciprocal crosses among them were made by hand emasculation and pollination in the greenhouse. Five crosses which produced adequate amounts of F1 seeds and their derived F2s and the parents were used for the purpose of this study. The results showed high heritability, high gain from selection and high coefficient of variation for GFR in two crosses only while GFD showed low values for these parameters in the same crosses. High heritabilities coupled with high gains from selection for yield and yield components indicated that selection for these traits in early generations may be effective. Non additive gene action were found to affect the grain filling duration suggesting that selection in advanced generations may be more appropriate than in early generation. Selection for grain filling rate and number of fertile tillers plant-1 can be recommended at early generations for all crosses except crosses 2B × 2A and 4B × 4A. Selection for grain yield might be appropriate in crosses 2B × 2A, 1A × 1B and 4B × 4A in early generation and in advanced generation in the other two crosses. High heritability values for the traits of the cross 2B × 2A, suggested that selection for yield improvement is possible in this cross. The high variability observed in these crosses offers good prospects for its improvement in the future.
Gaurav Khosla, B. S. Gill, T. P. Singh, Rahul Kapoor (India) Biomass, Harvest Index and Yield in Relation to Changes in Photo-thermal Regimes in Soybean (Glycine max L. Merrill.) Genotypes (pp 25-29)
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ABSTRACT
Original Research Paper: Fifteen photo- and thermo-insensitive early maturing genotypes and five promising main season normal maturing genotypes of soybean which were determinate in growth and photo-thermo sensitivity were evaluated for their agronomic performance under a wide range of photoperiod and temperature conditions manipulated through five sowing dates (February 23, March 20, April 14, May 9 and June 3). Genotypes, sowing dates and their interactions with environments were highly significant for the traits studied. The significant GE interactions for biomass production, harvest index (HI) and grain yield (GY) indicated that the tested genotypes ranked differently across diverse environments for these characters. In early maturing genotypes, longer day-length and higher temperature produced bold seeds and high HI but fewer yields. Main season genotypes produced higher biomass and GY than that of early maturing genotypes in all the sowings. Early maturing genotypes viz. E7 and E19 had higher GY whereas SL 295 and Pb. No. 1 recorded higher GY among main season genotypes over all the sowing dates. Biomass and HI were important determinants of GY as evident from their significant positive regression coefficients with GY. It is concluded that for main season genotypes (May and June sowing) GY can be increased by increasing HI and enhancement of biomass production in early maturing-photo and thermo insensitive in February-March sowing could lead in yield improvement. Study also demonstrated that early maturing photo-thermo insensitive genotypes of soybean could be grown successfully during spring/summer (February to June).
Reza Mohammadi, Reza Haghparast (Iran) Evaluation of Promising Rainfed Wheat Breeding Lines on Farmers’ Fields in the West of Iran (pp 30-36)
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ABSTRACT
Original Research Paper: The final stage of any crop breeding program is to evaluate the promising genotypes, which have been already selected in research stations, in farmers’ fields. This study was conducted to examine the superiority of 11 promising durum and bread wheat experimental lines against three farmers’ cultivars across five testing sites in 2006-07 cropping season in western Iran. In framers’ fields stability and genotypic superiority for grain yield were determined using genotype and genotype × environment (GGE) biplot analysis. The main objectives were to (i) examine whether the selected materials by breeders in research stations can also be successful on farmers’ field and (ii) recommend the best genotypes for farmers’ fields in western parts of Iran and possibly beyond. Analysis of genotype-by-farmers’ field trials data showed that the farmers’ fields main effect was the predominant source of variation. The genotype-by-farmers’ fields interaction was significant (P < 0.01), showing the changes in genotypes ranking in different farmers’ fields. The results showed that the promising durum wheat genotype Mrb3/Mna-1 with the highest yield performance and stability was widely adapted genotype to farmers’ fields. The bread wheat genotype PATO/CAL/3/7C//BB/CNO/5/CAL//CNO was adapted to some of farmers’ fields in western Iran, while the promising genotypes Ghafghaz//F9.10/Maya"s" and Momchil/Katya1 were more adapted to other farmers’ fields. The findings support that the farmers’ checks were outyielded by promising genotypes in farmers’ fields and verified yield improvements and stability are achieved by growing the promising lines on farmers’ fields under rainfed conditions.
Sunil Dutt Tyagi, Mudasir Hafiz Khan (India), Jaime A. Teixeira da Silva (Japan) Yield Stability of some Soybean Genotypes across Diverse Environments (pp 37-41)
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Original Research Paper: The present investigation was carried out to study stability performance over eight environments for seed yield and its components in 40 genetically diverse genotypes (37 indigenous + 3 exotic) of soybean (Glycine max L.) using a completely randomized block design. The partitioning of (environment + genotype × environment) mean squares showed that environments (linear) differed significantly and were quite diverse with regards to their effects on the performance of genotypes for fodder yield and the majority of yield components. The investigation revealed that the genotype MACS-47 was desirable and stable across the environments. Other genotypes PK-308, Bisra Soya, Indra Soya-9, Alankar and IS-22 were suitable for favorable environments while genotypes Pusa-16, Pusa-40, MACS-2, MACS-450 and JS-325 resulted in low seed yield in poor environments.
Ezatollah Farshadfar, Maryam Mohammadi, Reza Haghparast (Iran) Diallel Analysis of Agronomic, Physiological and Metabolite Indicators of Drought Tolerance in Bread Wheat (Triticum aestivum L.) (pp 42-47)
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ABSTRACT
Original Research Paper: Inheritance of grain yield, physiological and metabolite indicators of drought tolerance was studied in diallel F1 hybrids from 8 cultivars of Triticum aestivum, selected for their different responses to drought stress. Significant differences were found for grain yield (GY), relative water content (RWC), cell membrane stability (CMS), proline content (PC) and leaf chlorophyll content (LCC). Combining ability analysis indicated the involvement of additive and non-additive gene action in their inheritance. Parents 5 and 7 were the best general combiner for improvement of drought tolerance. The best specific combination with heterobeltiosis over the best parents for improvement of GY, RWC, CMC, PC and LCC were crosses 4×6, 1×6, 6×8, 3×8 and 2×3, respectively. High broad sense heritability observed for all the traits, but the rule of additive part was low. Graphic analysis showed that inheritance varied from dominance to overdominance, but presence of overdominance was exhibited for GY, RWC, PC and LCC. Non- allelic interaction was also found for PC and LCC, therefore selection through selfing is not effective for improvement of PC and LCC.
Mahmoud E. S. Ottai, Magdy A. A. Al-Kordy (Egypt), Jaime A. Teixeira da Silva (Japan), Khalid A. El-Dougdoug (Egypt) Genetic Variability and Antiphytoviral Activity of Wild and Inbred Genotypes of Silybum marianum Varieties (pp 48-53)
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Original Research Paper: Wild and inbred genotypes of Silybum marianum were assessed for five quantitative characters, silymarin production and its potent antiviral activities. Purple, white and wild varieties as well as their genotypes showed significant genetic variations in all characters except for the number of main branches/plant. Correlation coefficients showed highly significant values in all varieties while significant regression values were computed for plant height and total branches each with head flowers, in addition to seed yield with total branches in all. Six silymarin components were detected showing high variation among varieties and genotypes. Purple genotype P34 and white W9 were the best genotypes as they presented the maximum mean value for all studied characters and the highest silymarin content (30.20 and 62.85 mg/g, respectively). The seed methanolic extract of all genotypes had an inhibitory effect on Tomato mosaic virus (ToMV) infectivity. The extract reduced ToMV infection with different percentages: 80% for wild, 71.4, 69.6, 68 for white genotypes (W9, W2 and W13), and 60, 58.4 and 46.4, for purple genotypes (P34, P22 and P28). All silymarin constituents had a highly significant negative correlation with the number of local lesions. However, both in vivo and in vitro tests showed the inhibitory effect of the methanolic extract on virus infectivity. However, ToMV post-inoculation rubbing with the methanolic extract reduced ToMV infectivity more effectively than ToMV pre-inoculation. However, the wild S. marianum extract more effectively reduced ToMV infectivity in vivo than in vitro.
Peter Ejimofor Ogbonna, Ignatus Ugwudike Obi (Nigeria) Studies of Gene Effects on Yield and Yield Components in “Egusi” Melon (Colocynthis citrullus L.) (pp 54-57)
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Original Research Paper: Estimates of gene effects for number of fruits/plant, weight of fruits/plant, average fruit weight, seed yield/plant, number of seeds/plant, seed yield/fruit, number of seeds/fruit and 100-seed weight were made on “Egusi” melon (Colocynthis citrullus L.). The dominance (d) gene effect was more important than the additive (a) gene effect in the inheritance of these attributes. The epistatic gene effects made a high contribution and the dominance × dominance (dd) gene effect exhibited greater influence among the epistatic genes in most of the attributes. The implications of these findings are discussed and Reciporal Recurrent Selection is suggested as the breeding method for the improvement of these attributes.
Benedict C. Oyiga, Michael I. Uguru (Nigeria) Genetic Variations and Contributions of Some Floral Traits to Pod Yield in Bambara Groundnut (Vigna subterranea L. Verdc) under Two Cropping Seasons in the Derived Savanna of the South-East Nigeria (pp 58-63)
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Original Research Paper: This study was conducted to determine the genetic variation, character association and path coefficient analysis between floral traits and pod yield of 13 bambara groundnut (Vigna subterranea L. Verdc) genotypes. The genotypes were evaluated in replicated field experiments at the Deptartment of Crop Science Research Field, University of Nigeria, Nsukka in the early and late planting seasons. The result showed significant differences among the genotypes in most of the traits studied. The genotypic and heritabilty estimates were high in pistil length, stamen length and stigma-anther separation at both planting dates indicating that these traits have high transmitting ability to next generation and therefore, selection of these traits would be more efficient. The number of pods per plant had significant positive correlation with anther diameter in the early planting . However, number of pods per plant recorded negative correlation values with stigma-anther separation in the early and late planting indicating that decrease in stigma-anther separation will favour pod set in bambara groundnut. The path coefficient analysis showed that anther diameter had the highest positive direct effect (0.57) on number of pods per plant, followed by pistil length (0.25) in the early planting. In the late planting, stamen length had the largest positive direct effect (1.19) on number of pods but was masked by the negative indirect effect via pistil length (-1.27) and stigma-anther separation (-0.44) resulting in the significant negative correlation of the number of pods per plant with stamen length. Therefore, genotypes with large anthers could be reliably looked for, while selecting high yielding genotypes in the early planting. However, selection of genotypes with reduced stigma–anther separation and shorter pistil should be adopted in the improvement of the crop during late planting.
Michael I. Uguru, Josiah C. Onovo (Nigeria) Gender in Fluted Pumpkin (Telfairia occidentalis Hook. F.) (pp 64-66)
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Short Communication: A cytogenetic investigation was conducted on four lines of fluted pumpkin (Telfairia occidentalis Hook. F.) using the cold-induced pretreatment method as an integral part of the conventional technique. One major objective was to establish the chromosomal basis for sexual dimorphism in the crop. The results revealed a diploid chromosome number of 2n = 22. The chromosomes are mainly metacentric and submetacentric with only chromosome pairs 10 and 11 being subtelocentric and telocentric, respectively. The karyotypic analysis revealed that chromosome pair number 5 is homomorphic in the female plant but heteromorphic in the male plant. The ideograms showed that the chromosome complement falls into 11 size class groups of one chromosome pair per class in the female and 12 size class groups with the 5th chromosome pair having two size groups arising from the non-identical lengths in the male. This would appear to implicate an XY system of sex chromosomes with homogametic XX female and heterogametic XY male in fluted pumpkin.
Slim Amine, Ayed Sourour, Slama-Ayed Olfa (Tunisia), Jaime A. Teixeira da Silva (Japan), Slim-Amara Hajer (Tunisia) Morphological Diversity of Some Qualitative Traits in Tetraploid Wheat Landrace Populations Collected in the South of Tunisia (pp 67-70)
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Short Communication: When indigenous Tunisian durum wheat germplasm were evaluated by quantitative parameters, significant richness was observed. There are few reports on genetic variation of Tunisian durum wheat landraces based on morphological and qualitative traits. A total of 368 accessions of durum wheat (Triticum durum Desf.) were evaluated in 3 different regions in the south of Tunisia: Soukra (66 accessions), Matmata (145 accessions) and Toujene (157 accessions) using 9 qualitative traits. Phenotypic diversity indices (H′) were calculated for different traits and collection regions. Polymorphism was high for awn anthocyanin coloration (H′ = 1.18), spike glaucosity (0.89), hairiness on the external surface (0.88), awn colour (0.78), and awn length in relation to the spike (0.77). However, H′ estimates were relatively low for awn length (0.14), length of brush hair in dorsal view (0.30) and shoulder width (0.37). The pattern of variation of individual traits varied among regions. The Shannon-Weaver diversity index (H′) estimates for Matmata and Toujene, 0.75 and 0.61, respectively, were best among the three regions. Principal component analysis (PCA) explained 45.64 and 45.31% of total variability in Matmata and Toujene, respectively. This analysis classified the 145 Matmata accessions into two groups and the 157 Toujene accessions into four groups according to their similarity. These values showed that this germplasm has a relatively important diversity, confirming that Tunisia is one of the principal durum wheat centres of diversity.
Dorcas Olubunmi Ibitoye, Pamela Eloho Akin-Idowu (Nigeria) Intra-specific Hybridization in Cultivated Papaya (Carica papaya L.) Genotypes (pp 71-73)
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Research Note: A pioneer breeding study was started at the National Horticultural Research Institute, Ibadan, Nigeria during 2007-2008 on papaya with the aim of addressing the age-long problem associated with seedling sex identification in papaya, which is a major limiting factor in Nigeria for large-scale production of papaya. Morphological and qualitative characters were recorded for the selected parental genotypes and the F1 progenies. F1 hermaphrodite plants had lower mean value for plant height than both parents but had higher mean value for stem girth and number of leaves at flowering than one parent. The study revealed that controlled pollination of the hermaphroditic papaya genotypes segregated for female and hermaphrodite progenies at the first filial generation (F1) while the progenies resulting from male-female crosses segregated for male, female and hermaphrodite genotypes. The highest percentage hybridization success (70.2%) was recorded from selfed hermaphrodites. This result implies that generating more hermaphrodite genotypes under controlled pollination will give desired sex types needed to increase production. |
