Yield Related Characters Research Articles

Systematic trait based identification and characterization of Indian wheat varieties released during different time scales

Aim: Wheat varieties have been developed for yield improvement by modern plant breeding methods from the basic pedigree for long which brought about a restricted hereditary base. Therefore, the present study was designed to develop identification keys and characterize different wheat varieties on the basis of multiple traits. Methodology: Thirty-four Indian wheat (Triticum spp.) varieties released during different time scales were assessed for diversity through various approaches based on morphological, seed vigour, biochemical and molecular characterization.? Results: The results revealed that a considerable amount of variation was present in phenotypic characters such as flag leaf, plant height, spike and yield related characters. Seed vigour parameters included test weight, seedling dry weight, seedling length, accelerated ageing test and vigour indices showed significant variability among varieties. Dehydrogenase activity, tetrazolium test and electrical conductivity of seed leachates were also found worth studying for diversity. Molecular characterization included twenty-one SSRs selected after screening of 45, amplified 46 alleles, among them 42 alleles were polymorphic. PIC value varied from 0.1 to 0.65 and similarity coefficient extended from 0.34 to 0.87. Interpretation: Genetic diversity pattern analysis of genotypes based on their geographical origin did not show any clear relation, however characters like plant height, seed boldness and seedling vigour indices of varieties showed a trend with a chronology of their release. Different perspectives used in the study successfully categorized wheat genotypes into various groups.

Assessment of yield components of some cassava (Manihot esculenta Crantz) genotypes using multivariate analysis such as path coefficients

Abstract Cassava, which is a tropical storage root crop, serves as a veritable source of carbohydrate for people living in Sub-Saharan Africa. It is also an important source of industrial starch, biopolymers, animal feeds and ethanol. However, the genetic improvement of the crop is impeded by dearth in information on its genetic variability. A field experiment was carried out at the National Root Crops Research Institute, Umudike (05° 29′ N; 07° 33′ E; 122 m a.s.l.), Nigeria, aimed at assessing the interrelationship between fresh root yield and thirteen quantitative yield-related characters of twenty-eight (28) newly developed cassava genotypes. The rain-fed experiment was laid out in a randomized complete block design with dual replications in 2016/2017 cropping seasons. The results indicated that the newly developed cassava genotypes [2] NR110315 followed by [20] B1-5 and [1] NR110238 exhibited (P < 0.05) highest fresh root yield among the twenty-eight genotypes tested. The fresh root yield of [2] NR110315 (18.77 Mt ha−1) was relatively higher compared with [18] NR050080, which gave the least root yield of 5.38 Mt ha−1. The correlation coefficients obtained from the associations among the variables were positive and exhibited highly significant (P ≤ 0.01) association, especially between leaf area index (LAI) and root diameter as well as with fresh root yield of cassava. Among the nine variables subjected to the path analysis, LAI, starch content, above ground dry matter (AGDM), weight of fresh marketable roots per plant and root length that contributed positively and directly to higher fresh root yield require greater attention during selection and breeding in cassava studies. The direct effect of the variables indicating their magnitudes in decreasing order showed that LAI exhibited the greatest effect followed by starch content, AGDM, weight of fresh marketable roots plant−1, root length, % cassava bacterial blight incidence and % Cassava mosaic disease incidence, which had the lowest direct effect on root yield of cassava. Cyanide potential exhibited a direct, weak and negative effect on fresh root yield. The results further suggested that cassava improvement could be achieved through these characters that have positive and highly significant magnitude effect on fresh root yield.

Deficiency of mitochondrial outer membrane protein 64 confers rice resistance to both piercing-sucking and chewing insects in rice.

The brown planthopper (BPH) and striped stem borer (SSB) are the most devastating insect pests in rice (Oryza sativa) producing areas. Screening for endogenous resistant genes is the most practical strategy for rice insect-resistance breeding. Forty-five mutants showing high resistance against BPH were identified in a rice T-DNA insertion population (11,000 putative homozygous lines) after 4 years of large-scale field BPH-resistance phenotype screening. Detailed analysis showed that deficiency of rice mitochondrial outer membrane protein 64 (OM64) gene resulted in increased resistance to BPH. Mitochondrial outer membrane protein 64 protein is located in the outer mitochondrial membrane by subcellular localization and its deficiency constitutively activated hydrogen peroxide (H2 O2 ) signaling, which stimulated antibiosis and tolerance to BPH. The om64 mutant also showed enhanced resistance to SSB, a chewing insect, which was due to promotion of Jasmonic acid biosynthesis and related responses. Importantly, om64 plants presented no significant changes in rice yield-related characters. This study confirmed OM64 as a negative regulator of rice herbivore resistance through regulating H2 O2 production. Mitochondrial outer membrane protein 64 is a potentially efficient candidate to improve BPH and SSB resistance through gene deletion. Why the om64 mutant was resistant to both piercing-sucking and chewing insects via a gene deficiency in mitochondria is discussed.

Screening diverse soybean genotypes for drought tolerance by membership function value based on multiple traits and drought-tolerant coefficient of yield

BackgroundDrought is a major limiting factor seriously influencing worldwide soybean production and its impact on yield, morphological and physiological traits depend on the timing it occurs and the intensity of water shortage. Only limited research has however been conducted on identifying the drought-tolerant genotypes at different growth stages (vegetative growth phase, reproductive growth phase and the whole growth phase) as well as evaluate the effectiveness and reliability of multiple phenotypic and yield-related characteristics in soybean.ResultsTwo pot experiments and a 2-year field experiment were conducted to evaluate soybean drought tolerance at different growth stages. The membership function value of drought tolerance (MFVD) was used to identify drought-resistant cultivars during vegetative growth phase and reproductive growth stage; the relative drought index (RDI) of yield was used to assess drought-resistant cultivars during the whole growing period. In this study, regression models built based on MFVD indicated that the variation of drought tolerant coefficient (DC) of R/S, TRL, LAI and RSR could explain 73.70% of the total variation at vegetative growth phase. However, higher heritability only found in LAI and RSR, indicating the two traits could serve as reliable criteria for drought evaluation. Similarly, the DC of SPP, YPP, PH, PB, MSNN and STB could explain 94.30% of the total variation in MFVD according to stepwise multiple linear regression analyses at reproductive growth phase. Thus, these six traits were identified as indicators for screening drought resistance genotypes in soybean. In addition, correlation analysis revealed that the MFVD was significantly positively correlated with the DCRB, DCR/S, DCRSA, DCRSR and DCRBR at vegetative growth phase and DCYPP, DCSPP, DCRB, and DCPB at reproductive growth phase. This indicated that these traits were closely related to the drought resistance of plants.ConclusionsLD24, JD36 and TF31 of vegetative growth phase, and TD37 and LD26 of reproductive growth phase were identified with drought tolerant and highly drought tolerant, respectively. Moreover, 30 accessions with drought tolerance were screened in the field trial and could be applied for the drought resistance of other genotypes by cross-breeding.

Effects of Different Chemical Fertilizers Application Rates and Densities on the Whole Growth Period of Sorghum in Semi-Arid Areas of North China

Sorghum is one of the most important economic crops in the semi-arid areas of northern China. However, its yield is still relatively low, and some factors, such as the amount of different chemical fertilizers application and planting density, limit the increase of yield. In order to study the effect of fertilizer application rate and planting density on the growth and yield of sorghum, Longza 16 was used as test variety material, and the experiment was conducted with the split plot design. The fertilizer application (375kg/hm2(N:P:K=1:0.7:0.4), 375kg/hm2(N:P:K=1:0.7:0.8), 375kg/hm2 (N:P:K=1:0.7:1.6), 750kg/hm2（N:P:K=1:0.7:0.8), 750kg/hm2（N:P:K=1:0.7:1.6)) was designed as main plot and planting density (96000 plants/hm2, 109000 plants/hm2, 128000 plants/hm2, 154000 plants/hm2）was arranged as subplot. The photosynthetic parameters and yield-related characters were determined during the whole growth period of sorghum. The results showed that the effect of fertilizer application on the yield of sorghum was significant. The yield increased with the increase of fertilizer application, and the yield of 750kg/hm2 (N:P:K=1:0.7:1.6) was significantly higher than that of other treatments. Different planting densities also had a significant effect on the yield, showing that the yield increased with the increase of density, and the yield was the highest under the density of 154000 plants/hm2. In addition, the result of composite effect of fertilizer application rate and density showed that the yield of the treatment of 750kg/hm2 (N:P:K=1:0.7:1.6) and 154000 plants/hm2 was the highest, which was considered to be more suitable for the production of sorghum in the semi-arid areas of northern China.

Various tillage systems and sowing methods affect growth and yield related characters of cotton

Seedbed preparation and sowing methods play significant role in obtaining good crop yields. To explore the agronomic productivity and economic efficacy of different tillage and sowing methods in cotton, a two year field study was conducted during 2010 and 2011. The experiment comprised of two tillage systems viz; conventional tillage (one time disc harrow + two cultivations + planking) and deep tillage (chiseling twice + one cultivation + planking) along with three sowing methods viz; flat sowing, ridge sowing and bed sowing. Split plot design was used with three replications. Deep tillage amplified seed cotton yields by 18.7% and 11.14% during 2010 and 2011, respectively. Bed sowing exhibited higher yield contributing traits such as number of opened bolls per plant and boll weight as compared to ridge and flat sowing. Deep tillage with bed sowing gave maximum net returns of USD 1407.88 with BCR of 1.81 during the year 2010, while during 2011 it was USD 783.50 with BCR 1.45. Bulk density of the soil was found lower in the upper layer of soil surface as compared to lower surface under deep tillage systems as compared to conventional tillage systems. It was concluded that deep tillage produced more number of plants which contributed towards highest seed cotton yield. Moreover deep tillage was more costly except in bed sowing of cotton crop. The interactive effect of tillage systems and sowing methods were found non significant during both years of study.

Correlation and path coefficient analysis of seed yield and yield related characters in sesame (Sesamum indicum L.)

Correlation and path analysis were carried out to determine the effects of various traits as components of seed yield in 40 sesame genotypes. The genotypes were evaluated in RBD with three replications during kharif 2018 at the Research Farm of Agricultural Research Station, Agriculture University, Jodhpur, Rajasthan. Analysis of variance exhibited significant difference for all the characters suggesting the presence of inherent genetic variations among the genotypes studied. Correlation among the traits revealed that seed yield/plant was positively associated with number of capsules/plant, capsule bearing length, harvest index and number of primary branches at both genotypic and phenotypic levels, while, non-significant correlation with days to 50% flowering, days to maturity, plant height (cm), number of seeds per capsule and 1000-seed weight. The path coefficient analysis of different characters contributing towards seed yield/plant showed positive direct effect by number of capsules/plant. Capsule bearing length, harvest index, number of primary branches/plant, 1000-seed weight, plant height and days to 50% flowering showed considerable positive direct effect on seed yield. Indirect positive effect showed by days to 50% flowering via number of primary branches at genotypic level. These results indicated that number of primary branches/plant, number of capsules/plant, capsule bearing length and harvest index are the principal yield components, and selection for these traits may be useful in improving seed yield in sesame.

English

Understanding the genetic variability and diversity of crops is the basis for breeding and improving of crops. Sixty four Ethiopian hot pepper genotypes were evaluated in 8×8 simple lattice design for genetic variability in green fruit yield and yield related traits at Axum Agricultural Research Center during 2018/2019 under irrigation. Data were collected on green pod yield and yield related characters. The analysis of variance showed significant amount of variations among genotypes in their mean performances of studied traits. High heritability and genetic advance were observed for average fruit weight (145.03, 97.11), fruit length (97.43,98.62), number of fruits per plant (78.54,95.78), number of branches per plant (77.65, 98.64), green pod yield per plant (74.26,99.80) and fruit pericarp thickness (63.61,97.76), respectively. This indicates that these traits are predominantly governed by additive gene action. From correlation study fruit yield per plant exhibited highly significant positive association with average fruit weight (0.72, 0.71), fruit length (0.69, 0.68) and fruit diameter (0.61, 0.60)) at both genotypic and phenotypic levels, respectively. Fruit length had the highest direct effect (0.46) on fruit yield per plant, followed by average fruit weight (0.36). In general, result of this study indicated that average fruit weight, fruit length, fruit diameter and fruit pericarp thickness showed high heritability, genetic advance, positive correlation and high positive direct effects. Hence, these traits can be used as indirect selection criteria for hot pepper yield improvement program. Key words: GCV, genetic advance, heritability, PCV, pod yield, variability. &nbsp

Integration of soil and foliar nutrition in influencing the yield related characters, yield and economics of nendran banana (musa aab group) and the soil nutrient status of cropped field

Integration of soil and foliar nutrition in influencing the yield related characters, yield and economics of nendran banana (musa aab group) and the soil nutrient status of cropped field

Gümüşhacıköy Basma Bölgesi İçin Geliştirilen Hibrit Tütünlerin Verim ve Kalite Performansları

Gümüşhacıköy Basması, oryantal tip tütünler içinde aromatik yapısı ile ün yapmıştır. Ancak özellikle 2000‘li yılların başından itibaren düşen üretim miktarı nedeniyle, bu tip tütünlerin üretim sahasına Taşova, Erbaa ve Niksar hattı da katılarak, yeni oryantal tütün tiplerinin yaygınlaştırıldığı bilinmektedir. Bu araştırmada bazı oryantal tütün ebeveyn ve hibritlerinin Gümüşhacıköy ekolojik koşullarında verim ve kalite performansları ile bu hibritlerin heterosis ve heterobeltiosis değerleri incelenmiştir. Hibrit hatlar Xanthi-2A, Erbaa, Nail, Katerini ve Canik 10821 (Sıtmasuyu) genotiplerinden yarım diallel melezleme ile 2016 yılında elde edilmiştir. Çalışma 5 ebeveyn ve bunların hibritlerinden öne çıkan 4 F1 popülasyonu ile yürütülmüştür. Verim ve verim ile ilişkili özelliklerin (bitki boyu, yaprak sayısı, yaprak eni ve boyu) yanı sıra glikoz, fruktoz, nikotin, klorogenik asit ve rutin içerikleri incelenmiştir. Yaprak boyu dışındaki tüm özelliklerde genotiplerin istatistiki bakımdan çok önemli derecede farklılık gösterdiği belirlenmiştir. Bitki boyu ve yaprak sayısı dışındaki tüm parametrelerde hibritler, ebeveynlerinden daha iyi performans göstermiştir. Bu üstünlük verimde %8,42, randımanda %7,73, indirgen şekerde %8,64, nikotinde %3,49 ve klorogenik asit+rutinde %15,20 düzeyinde olmuştur. Verim üzerine yaprak eninin ve randıman üzerine ise klorogenik asit+rutin içeriğinin etkisi belirlenmiştir. Çalışma sonucunda heterosis ve heterobeltiosis verileri de değerlendirildiğinde Xanthi 2A x Katerini hibritinin ümitvar sonuçlar ortaya koyduğu tespit edilmiştir.

Correlations and Path Analysis of Some Quantitative and Qualitative Characters in Durum Wheat (Triticum turgidum L.) Accessions in Western Oromia, Ethiopia

Durum wheat is the second most important triticum species next to bread wheat. Ethiopia is one of the centers of diversity for durum wheat. The present study was to determine the interrelationship and direct and indirect effects of yield component traits on grain yield of Ethiopian landraces durum wheat for further breeding activities of yield improvement. Out, 97 durum wheat accessions along with 3 improved varieties were evaluated in 10 x 10 simple lattice design during 2018 main cropping season at Mata Sub site of Haro Sabu Agricultural Research Center. Analysis of variance revealed highly significant differences among accessions for all traits. More than 36% of accessions were superior in mean grain yield than the standard checks. Grain yield exhibited positive and significant correlation both at genotypic and phenotypic level with most of the characters such as plant height (rp = 0.22, rg = 0.25), harvest index (rp=0.79, rg = 0.78), biological yield (rp = 0.31, rg = 0.30), number of kernels per spike (rp = 0.17, rg = 0.21), spike length, (rp = 0.36, rg = 0.39), and hectoliter weight (kg hl -1 ) (rp = 0.44, rg = 0.45). The association between yield, and yield related characters through phenotypic genotypic path coefficients revealed that biological yield, spike length, harvest index and plant height exerted highest positive direct effect on grain yield. This suggests that simultaneous improvement in these characters might be possible Keywords: correlation, direct and indirect effects, durum wheat and path analys DOI : 10.7176/JBAH/9-21-03 Publication date: November 30 th 2019

Association mapping for agronomic traits in six-rowed spring barley from the USA harvested in Kazakhstan.

In barley, six-rowed barley is advantageous over two-rowed barley for feed due to the larger number of seeds per spike and the higher seed protein content. The growth of six-rowed barley is potentially important for breeding in agriculturally oriented countries, such as Kazakhstan. Nevertheless, until recently, very little attention was given to six-rowed barley in breeding projects in Kazakhstan, one of the largest countries in the world. In this study, phenotyping and single nucleotide polymorphism (SNP) genotyping data were generated from 275 accessions originating from six different breeding organizations in the USA as well as 9 accessions from Kazakhstan in field trials at six breeding institutions. The USA six-rowed barley was tested in comparison to local accessions over three years (2009–2011) based on analyses of key agronomic traits. It was determined that the average yield in the USA accessions in comparison to local lines showed heavier yield in all six tested sites. Principal Coordinate Analysis based on 1618 polymorphic SNP markers separated Kazakh lines from six USA barley origin groups based on PC1 (77.9%), and Montana lines from the remaining five USA groups based on PC2 (15.1%). A genome-wide association study based on eighteen field trials allowed the identification of 47 stable marker-trait associations (MTA) for ten agronomic traits, including key yield related characters such as yield per square meter, thousand grain weight, number of kernels per spike, and productive tillers. The comparison of chromosomal positions of identified MTA with positions of known genes and quantitative trait loci suggests that 25 out of those 47 MTAs are presumably novel. The analysis of 42 SNPs associated with 47 MTAs in the Ensemble genome annotation system (http://ensemblgenomes.org) suggested that 40 SNPs were in genic positions of the genome, as their sequences successfully aligned with corresponding Gen ID.

The effect of plant growth regulators on recovery of wheat physiological and yield-related characteristics at booting stage following chilling stress

Chilling stress has a strong negative impact on the growth and development of winter wheat (Triticum aestivum L.). To investigate the recovery of physiological function and yield formation by plant growth regulators following chilling stress, we performed low-temperature phytotron experiments at the booting stage, and sprayed 6-benzylamino adenine (6-BA), salicylic acid (SA), brassinolide (BR) and abscisic acid (ABA) after chilling stress. Plant growth regulators significantly enhanced SPAD value and net photosynthetic rate (Pn) in flag leaves following chilling stress (p < 0.05). Compared with the control group sprayed with distilled water, stomatal conductance (Gs) and transpiration rate (Tr) increased, while intercellular carbon dioxide concentration (Ci) decreased. In addition, the concentration of malondialdehyde (MDA) was significantly decreased, and the activities of superoxide dismutase (SOD) and peroxidase (POD) were enhanced (p < 0.05). Plant growth regulators also increased the grain filling rate during the 14 days after anthesis, thereby increasing grain weight. The grain number per spike, 1000-kernel weight, and yield per plant after harvest were also significantly enhanced (p < 0.05). Thus, spraying plant growth regulators at the booting stage relieved the adverse effects on physiological activity in wheat flag leaves caused by chilling stress, and 6-BA and SA were particularly effective.

Plant growth regulators: One of the techniques of enhancing growth and yield of Bangladeshi local cucumber variety (Cucumis sativus)

Cucumber (Cucumis sativus) is becoming an essential part of the regular food menu for both health cautiousness and its dietary value over other foods. Availability of high yielding cucumber variety is one of the major obstacles for cucumber production in Bangladesh. Plant growth regulators (PGRs) play a significant role to alter the various type of physiological and morphological characters in cucumber. In this research, Bangladeshi local cucumber variety ‘Baromashi’ was used to observe the effect of PGRs on growth and yield-related characters. Four different treatments (Control: untreated plant, T1: maleic hydrazide 200 ppm, T2: ethephon 300 ppm and T3: NAA (1-naphthaleneacetic acid) 18 ppm) were used. Application of PGRs showed an increased number of primary and secondary branches however, negative effect on stem length and node for the first flower was also observed. PGRs showed the opposite effect on the time required for the first flowering where male flower needed more time and female flower required less time compared to the untreated plants. In the case of fruit-related characters, PGRs possessed positive effect and ethephon 200 ppm showed the best result among the treatments. Total yield might be directly related to the number of branches as well as with the number of female flowers in local cucumber variety.

Genetic Analysis of Yield and Related Characters of Lablab Bean

An experiment was conducted with a view to determine the nature and extent of gene action of yield and yield related characters of lablab bean. Five parents and their 10 F1s synthesized from 5 x 5 half diallel cross were evaluated in a Randomized Complete Block Design with three replications. The analysis of variance showed that the difference among the genotypes (parents and F1s) were highly significant for all the characters which revealed the presence of wide variability among the genotypes under this study. Hayman’s ANOVA (modified by Jones) suggested that the presence of additive and dominance gene actions for all the characters. The ‘Vr-Wr’ graph indicated partial dominance for the characters viz. days to first inflorescence appearance, days to first flowering, days to pod maturity, days to seed maturity, number of nodes per inflorescence, edible pod length, edible pod breadth, edible pod weight and pod yield per plant. Over dominance was observed for number of inflorescences per plant, number of pods per inflorescence and hundred seed weight. Complete dominance was observed only for number of pods per plant in lablab bean. As the development of hybrid variety is not possible in lablab bean, diallel selective mating system may be adopted for improvement of yield traits by using knowledge of gene actions. The hybrids with predominant additive gene action for yield related traits may be advanced to obtain transgressive segregants and pure lines for higher pod yield per plant.

Disomic chromosome addition from Thinopyrum intermedium to bread wheat appears to confer stripe rust resistance

A wheat line 14-569 developed from a hybrid of common wheat cv. Chuannong 10 with the wheat–Thinopyrum intermedium partial amphiploid TAI7045 exhibits stable double spikelets per node character in the lower middle portion of a spike, is highly resistant to stripe rust, and produces kernels with a higher 1000-kernel weight than those of its wheat parent. Chromosome counting and an analysis of meiosis demonstrated that line 14-569 is a disomic addition line with 2n = 44, 22II. Sequential genomic in situ hybridization and non-denaturing fluorescence in situ hybridization analyses indicated that one pair of St-genomic chromosomes from Th. intermedium was added to the wheat complement and that the wheat complement included one pair of 1RS/1BL wheat–rye translocation chromosomes. PCR-based landmark unique gene molecular marker analysis revealed that the added pair of chromosomes comprised 3St chromosomes, which suggested that the added 3St chromosomes from Th. intermedium might carry the genes to control the high yield-related characters and stripe rust resistance. This addition line will potentially be useful resource for improvements in wheat yields and stripe rust resistance.

Morphological evaluation of wheat genotypes under simulated draught stress

Plant growth and productivity are greatly affected by environmental stresses such as drought, high salinity and low temperature. Abiotic stresses, notably extremes in temperature, water deficiency and salinity frequently limits the growth and productivity of major crop species such as wheat. Drought can affect vegetative and reproductive stages. Therefore, understanding plants’ responses to drought at every life stage is crucial to progress in genetic engineering and breeding. The aim of this study was to evaluate the 20 Wheat germplasm at morphological level under imposed draught stress. An experiment was conducted on 20 wheat genotypes in a Randomized Complete Blocks Design (RCBD) with three replicates under normal and terminal drought stress conditions conditions at laboratory of Department of Agriculture Biotechnology, S.V.P.U&T Meerut, India during rabi cropping seasons 2014–15 and 2015–16. According to the study of drought can reduce leafarea which can consequently lessen photosynthesis. Thus, on the basis of various morphological characters it is concluded that higher yield of K9351 and K1205 under non stress conditions might be on account of its higher yield potential. These genotypes exhibited higher yield under water stress owing to the existence of drought tolerance mechanism through better management of root shoot mechanism, leaf area and yield related characters. The results showed that induced draught stress significantly reduced their value with increasing stress level. However the germplasm K9351 and K1205 show very less effect of induced draught stress and maintained their yield potential even after the third level of stress condition. Therefore, these genotypes need to be utilized in future breeding program.

Assessment of combining ability effects using quality protein maize donors as testers for yield and yield traits in maize

The present study was accomplished to assess the general combining ability effects of parents and specific combining ability effects of hybrids for yield and yield related traits in maize. Sixty three F1 hybrids were developed and by crossing nine productive maize inbred lines with seven quality protein maize inbred testers in Line x Tester mating design and evaluated for twelve yield and yield related characters at CCSHAU, Regional Research Station, Karnal, Haryana. The combining ability analysis revealed the presence of higher magnitude of SCA than GCA variance for all characters under study except for number of grains per cob. The preponderance ratio of sca/gca variance revealed presence of non additive gene action in the expression of all the characters under study. Among the sixteen parents inbred lines viz., HKI 1040-4, HKI 323, HKI 161 and HKI 163 were found to be the best parent for grain yield and among the hybrids, HKI 1128 x HKI 163, HKI 659-3 x HKI 194-6, HKI 1126 x HKI 161, HKI 536YN x HKI 193-1 and HKI 488 x HKI 170(1+2) exhibited highest significant and favourable sca effects for yield and yield attributing characters.

English

Tef [Eragrostis tef (Zucc.) Trotter] is a tetraploid almanac plant which belongs to the grass family, Poaceae and plays a vital role in the Ethiopian national food. In this study, thirty-four F2 derived F7 recombinant tef inbred lines, two standard (Kora and Quncho) and one local checks were field evaluated for genetic variability in grain yield and yield related characters at Axum Agricultural Research Center in 2014 cropping season. Triplicated randomized complete block design was used. Data were collected on fourteen yield and yield related traits and the analysis of variance reveled that genotypes varied significantly for all traits studied except thousand kernel weight. Highest genotypic coefficient of variation (GCV) was computed for biomass yield followed by panicle yield, plant height and grain yield, in contrast, lowest GCV was noted for number of fertile tillers per plant, days to heading, days to maturity and lodging index, whereas the highest phenotypic coefficient of variation (PCV) was recorded for panicle yield, plant height, biomass production rate per day and biomass yield. The highest broad sense heritability values were recorded for plant height, biomass production rate per day, biomass yield, days to 50% heading and grain yield. The highest genetic advance as percent of mean was recorded for biomass production rate per day, biomass yield, grain yield and grain yield production rate per day, while the lowest genetic advance as a percent of mean was computed for number of productive tillers per plant, panicle length, days to heading and panicle weight. The overall study indicated that there were variations in magnitude of variability in traits for the genotypes studied which showed smooth selection for further improvement in tef. Key words: Genotypic coefficient of variation (GCV), genetic advance, heritability, phenotypic coefficient of variation (PCV), seed yield, variability. &nbsp

Combining ability analysis for earliness and yield related characters in pea (Pisum sativum)

A study was conducted on the combining ability analysis in a 11×11 half-diallel cross of garden pea (Pisum sativum L.). F1 hybrids (55) along with 11 parental lines were grown in randomized block design with three replications. The mean square due to GCA and SCA were highly significant for all the characters indicating the importance of additive and non-additive genetic components for the characters under study. Further, σ2s was more than σ2g for all the characters suggested the importance of non-additive variance for the improvement of these characters. The parents P2 (GP-17), P5 (GP-473) and P7 (VRP-7) were observed to be good combiners for most characters under study including yield per plant. The crosses P6 × P10, P2 × P8 and P8 × P10 were most promising combinations for total yield per plant. The results indicated the importance of recombinant breeding for effective utilization of non-additive genetic variance in garden pea.