High Broad Sense Heritability Research Articles

Evaluation of sugarcane promising clones based on the morphophysiological traits developed from fuzz.

Sugarcane is one of the critical commercial crops and principal sources of ethanol and sugar worldwide. Unfavorable conditions and poor seed setting rates hinder variety development in sugarcane. Countries like Pakistan directly import fuzz (true seed) and other propagation material from the USA, China, Brazil, etc. In this study, we imported fuzz from China, developed 29 genotypes germinating in the glasshouse, and evaluated at field conditions along with two local checks (CPF-251 and HSF-240). Morphophysiological data were recorded, including plant height (PH), cane length (CL), internodal length (IL), tiller number (TN), brix percentage (B), cane diameter (CD), chlorophyll a (Chl. a), chlorophyll b (Chl. b), and total chlorophyll (T. Chl). Results showed highly significant (p < 0.001) differences among the sugarcane accessions for all the studied traits. High broad-sense heritability (81.89% to 99.91%) was recorded for all the studied parameters. Genetic Advance (GA) ranges from 4.6% to 65.32%. The highest GA was observed for PH (65.32%), followed by CL (63.28%). Chlorophyll leaching assay was also performed at different time points (0, 50, 100, 150, and 200 min). All the genotypes showed the same leaching trend at all times, and better performing genotypes showed less leaching compared to poor performing, indicating the high amount of cutin and wax on the leaf surface. Correlation analysis showed that PH, CL, IL, and TN had significant associations. Principal components analysis (PCA) further confirms these results. Based on PCA and correlation results, PH, CL, IL, and TN can be utilized as a selection criterion for sugarcane improvement. Genotypes such as NS-4a, NS-5, NS-6, NS-8, NS-9, and NS-15 are recommended for future breeding programs related to sugarcane variety development.

Genetic variability of F2 foxtail millet population derived from ICERI-5 and Botok-10 cross

Abstract. Sintia M, Ardie SW, Suwarno WB. 2023. Genetic variability of F2 foxtail millet population derived from ICERI-5 and Botok-10 cross. Biodiversitas 24: 3559-3567. Foxtail millet (Setaria italica (L.) P. Beauv.) is a carbohydrate source with good tolerance to abiotic stress. High productivity, short stature, and early flowering time are the breeding targets of this species. This study aimed to obtain genetic variability of F2 foxtail millet population derived from ICERI-5 and Botok-10 crossand to predict selection response based onweighted selection index. This experiment was conducted in Bogor and consisted of 522 F2 individuals and two parental genotypes. The results showed that the F2 population had shorter plant height and earlier flowering time compared to Botok-10, and higher grainweight per plant compared to ICERI-5. Plant height, flowering time, and grainweight per plant showed moderate to high genotypic coefficient of variation with moderate to high broad-sense heritability. Weighted selection index using the three target traits resulted in ten F2 individuals with higher selection index compared to both parents, with individual number I5B10-4-96 having the highest selection index. Selection responses based on a weighted selection index indicate an expected decrease in flowering time and an increase in grain weight per plant in the next generation.

Genotypic and Phenotypic Variability and Correlation Studies in Ridge Gourd (Luffa acutangula L. Ruxb.)

The research was conducted AICRP on Vegetable crops, Department of Horticulture, MPKV, Rahuri, Dist. Ahmednagar (M.S.) in RBD along with two replications evaluated that summer-2022. In F3 progenies in Cross-III P6 x P8 (Saloni-5 x NRG-9) with two parents ridge gourd. In eighteen characters studied that variability and broad sense heritability (bs) with genetic advance over mean and correlation studied that, the high GCV and high PCV observed for the number of branches/vine, fruit yield/vine, fruit yield/plot and fruit yield/ha reported that highest variability indicated characters for further improvement and the highest broad sense heritability (bs) along with the highest genetic advance over mean were observed in number of branches/vine, number of nodes which first male flower appeared, number of picking, weight of fruit, number of fruits/vine, fruit yield/vine, fruit yield/plot and fruit yield/ha. The fruit yield (q/ha) in F3 generation at genotypical and phenotypical of fruit yield indicated that highly significant positively correlated with number of branches/vine, length of vine, number of pickings, days to last pickings, diameter of fruit except genotypic level, weight of fruits and number of fruits/vine, in these characters was governed by additively gene action, the least influences by the environment effects indicating that better chance for the improve through the selections.

Genetic Variability and Heritability of Seed Protein Content in Vigna unguiculata L. Walp. Genotypes Grown in Two Agro-Ecological Environments of Chad

Cowpea is an important pulse crop grown in sub-Saharan Africa and in parts of Asia and the Americas. Cowpea seed is an affordable source of nutrients rich in protein with number of essential amino acids. Dehulled seeds of eight improved cowpea lines grown in N’Djamena and Bebedjia (Chad) were analyzed for seed protein content in order to assess the variability, the heritability and the effect of environment interaction. In each locality, the experimental design was a triplicated randomly complete block design. The results showed a wide variability among genotypes for crude seed protein content. The mean value of crude seed protein content was 25.55% with varieties TN-27-80, TN-985-61399 and TN-5-78 showing highest values. High heritability in broad-sense (h2 = 0.74) and moderate genetic advance (GA = 14%) estimated for this character indicated the scope for improvement through selection. The effects of genotype (83.1% of the total sum of square), location (3.5%) and their interaction (13.4%) were highly significant (P&lt;0.01), but the protein content was slightly influenced by the environment. High potential for breeding programs is expected as genetic factors are believed to account for the main variation in protein content. This research could provide information for breeders to develop cowpea cultivars with higher protein content.

Study of Four Cucumber Germplasm Genotypes, Grown in Qatar and the Indian Agro-climatic Zone, Based on Its Phenotypic Traits

This study included four genotypes of cucumber (IC257296, IC420405, GYNE-5, PUSA SANYOG) which were evaluated based on phenotypic traits when grown under two different soil zones of Doha (Qatar) and Meerut (India). Statistical analysis to estimate various genetic parameters like phenotypic and genotypic variance, phenotypic and genotypic coefficient of variation (PCV and GCV), broad sense heritability and genetic gain and principal component analysis (PCA) of genotypes was done in order to assess the magnitude of variability for various agro-metrical characters. In Indian soil zone, highest yield was observed in GYNE-5, while, in Qatar soil zone, highest yield was observed in PUSA SANYOG. The phenotypic coefficient of variation (PCV) was higher than its corresponding genotypic counterpart (GCV) for all characters studied. High broad-sense heritability was associated with all the traits in both zones except fruit length. Days to edible maturity, fruit length and fruit width showed low genetic gain in qatar zone; hence, heterosis breeding would be recommended. Principal component analysis involved vine length and days to edible maturity as the most discriminating trait that accounted for greater variability in cucumber in qatar zone, and it should be considered in cucumber improvement programs. Correlation analysis represent that yield was positively correlated with fruit length and fruit width, while, fruit per plant showed positive significant correlation with vine length. Present findings suggest that PUSA SANYOG may be cultivated in other areas with similar climatic conditions. This study will help to improve the protected agriculture model of Qatar and revenue generation for the farmers.

Studies on Genetic Variability and Character Association for Quantitative Traits of Garden Pea (Pisum sativum L.)

The field experiment was carried out in randomized block design repeating each genotype into 3 blocks at Agriculture Farm of Lovely Professional University, Jalandhar, Punjab, India during rabi season (November–March) of 2015–16. Variability in the breeding population is essential pre-requisite to improve yield, earliness, disease resistance, lodging resistance etc. and the study of correlation and path analysis help in formulating selection indices for yield improvement. Therefore, a study was carried out undertaken to assess the magnitude of genetic variability and character association in twenty four diverse genotypes of garden pea (Pisum sativum L.) based on eleven quantitative characters. Analysis Of Variance (ANOVA) showed the existence of wide variability among the genotypes for all the characters studied. Closer magnitude of genotypic and phenotypic variation also indicated the presence of considerable genetic variability for all characters. High proportion of GCV accompanied with high heritability (in broad sense) and high genetic gain/genetic advance as percentage of mean were recorded for the characters like days to 50% flowering, plant height, harvesting span, dry matter and pod yield. Significant positive genotypic and phenotypic correlations were observed among pod yield and days to 50% flowering, number of pods plant-1 and number of seeds pod-1. These characters also had positive direct effect on pod yield. Hence, it can be concluded that selection is feasible for improvement of the characters studied under investigation.

Genetic dissection of QTLs for oil content in four maize DH populations.

Oil is one of the main components in maize kernels. Increasing the total oil content (TOC) is favorable to optimize feeding requirement by improving maize quality. To better understand the genetic basis of TOC, quantitative trait loci (QTL) in four double haploid (DH) populations were explored. TOC exhibited continuously and approximately normal distribution in the four populations. The moderate to high broad-sense heritability (67.00-86.60%) indicated that the majority of TOC variations are controlled by genetic factors. A total of 16 QTLs were identified across all chromosomes in a range of 3.49-30.84% in term of phenotypic variation explained. Among them, six QTLs were identified as the major QTLs that explained phenotypic variation larger than 10%. Especially, qOC-1-3 and qOC-2-3 on chromosome 9 were recognized as the largest effect QTLs with 30.84% and 21.74% of phenotypic variance, respectively. Seventeen well-known genes involved in fatty acid metabolic pathway located within QTL intervals. These QTLs will enhance our understanding of the genetic basis of TOC in maize and offer prospective routes to clone candidate genes regulating TOC for breeding program to cultivate maize varieties with the better grain quality.

Genetic markers and tree properties predicting wood biorefining potential in aspen (Populus tremula) bioenergy feedstock

BackgroundWood represents the majority of the biomass on land and constitutes a renewable source of biofuels and other bioproducts. However, wood is recalcitrant to bioconversion, raising a need for feedstock improvement in production of, for instance, biofuels. We investigated the properties of wood that affect bioconversion, as well as the underlying genetics, to help identify superior tree feedstocks for biorefining.ResultsWe recorded 65 wood-related and growth traits in a population of 113 natural aspen genotypes from Sweden (https://doi.org/10.5061/dryad.gtht76hrd). These traits included three growth and field performance traits, 20 traits for wood chemical composition, 17 traits for wood anatomy and structure, and 25 wood saccharification traits as indicators of bioconversion potential. Glucose release after saccharification with acidic pretreatment correlated positively with tree stem height and diameter and the carbohydrate content of the wood, and negatively with the content of lignin and the hemicellulose sugar units. Most of these traits displayed extensive natural variation within the aspen population and high broad-sense heritability, supporting their potential in genetic improvement of feedstocks towards improved bioconversion. Finally, a genome-wide association study (GWAS) revealed 13 genetic loci for saccharification yield (on a whole-tree-biomass basis), with six of them intersecting with associations for either height or stem diameter of the trees.ConclusionsThe simple growth traits of stem height and diameter were identified as good predictors of wood saccharification yield in aspen trees. GWAS elucidated the underlying genetics, revealing putative genetic markers for bioconversion of bioenergy tree feedstocks.

Efficiency of index-based selection for potential yield in durum wheat [&lt;em&gt;Triticum turgidum&lt;/em&gt; (L.) ssp. &lt;em&gt;turgidum convar. durum&lt;/em&gt; (Desf.) Mackey] lines

Wheat is a socioeconomically important crop in Algeria. Improving genetic gain of quantitative traits through selection is at the core of every successful breeding program. Selection is usually performed on grain yield, but other agronomically related characteristics can also help increase genetic gain through indirect or multi-trait selection. The objective of this work was to quantify genetic parameters and compare the efficiency of direct, indirect and simultaneous selection methods in terms of predicted genetic values of wheat progenies. For this purpose, 418 F4-derived lines were evaluated for six agronomic traits including heading date, flag leaf area, plant height, number of spikes, thousand kernel weight and grain yield in an augmented block design with three check varieties. Wide genetic variation with moderately high broad-sense heritability were observed for the recorded traits, except for heading date. The results from genetic gain revealed variation in gains for assessed traits and breeding methods employed. The classic index of Smith and Hazel (SHI) demonstrated a similar genetic gain in grain yield compared to gain from direct selection. Generally, the selection-based index showed the highest responses considering all traits simultaneously with a slight inferiority of the SHI index. The coincidence rates among the evaluated indices were higher than those obtained between the measured traits. Based on the comparisons between the selected lines, the SHI index and the selection base index of Williams were similar to grain yield and can reach up to 79.51% coincidence of breeding lines identified by these selection criteria. Breeding lines L252, L34, L24, L130 and L413 were the most common individuals identified according to number of coincidences from the different selection methods used. Of these, L34 and L24, and to a lesser extent L15 can be considered promising wheat lines for improving grain yield.

Genetic analysis of anthracnose resistant and heat tolerant chili inbreed lines based on morpho-physiological characteristics

A better understanding of the various desirable characteristics present in chili (Capsicum annuum L.) genotypes has aided in developing more effective selection methods for crop improvement. Identifying genetically superior parents is critical in selecting the best parents and inbred lines for breeding purposes. This study was conducted over two planting seasons in glasshouse using morpho-physiological parameters to evaluate the heritability variation of selected chili genotypes based on their genetic diversity for future breeding program. Significant variances were observed in all the studied parameters across the chili pepper accessions with an inclusive range of diversity. The highest genotypic coefficient of variation (≥ 20%) was observed for all physiological and yield characteristics. While the highest phenotypic coefficient of variation (≥ 20%) was seen for all examined characteristics. All studied parameter had high broad sense heritability (˃ 55%) except total number of branches per plant (47.9%) while the moderate to high genetic advance were observer for all studied traits demonstrating that the extents of heritability and variability are due to their genetic makeup and environment had little influence on these characters. The evaluated genotypes were grouped into seven clusters based on the cluster analysis and Group I recorded highest yield with eight genotypes while Groups III, IV, V, VI, and VII recorded one each. Plant height and total branch number showed a highly significant positive correlation with the number of fruits per plant and yield per plant. Similarly, the number of fruits per plant had a highly significant positive correlation with fruit yield per plant. The study revealed that genetic variability might be usefully exploited through selection for further breeding purposes to increase yield and production.

Effects of orange rust on sugarcane yield traits in a multi-environment breeding program

Orange rust caused by Puccinia kuehnii is a major emerging disease in many sugarcane-producing countries. Breeding for resistant varieties is the main strategy for controlling orange rust. The rapid spread of this disease in recently contaminated sugarcane industries offers the opportunity to use on-going breeding trials to investigate the effect of orange rust on yield traits and gauge levels of resistance required to minimize losses. Orange rust was first observed in 2018 in Reunion. This study reports the effects of the disease on cane yield (CY), recoverable sugar (RS), fiber content (FIB) and economic index (EI) in five environments of Reunion’s sugarcane breeding program located in diverse agro-climatic zones. Disease resistance assessed under natural infection had high broad-sense heritability (0.76–0.91) in multi-environment analyses. Mean infection levels differed between locations congruently with location differences for two influential climatic parameters (humidity and temperature). Maximum potential yield losses ({YL}_{max}) associated with orange rust were estimated using regression analyses of yield traits versus disease susceptibility. {YL}_{max} for CY and EI varied between environments and reached up to 26.0% and 24.2% respectively, in one of the most humid environments. RS was either unaffected or only slightly increased by the disease. In contrast, FIB was always reduced by the disease ({YL}_{max}≤6.5%). Multi-environment analyses of yield traits of varieties common to all five environments gave insights into the impact of orange rust on the yielding ability of these varieties across all environments. All these data provide food for thoughts to efficient breeding strategies for varietal resistance to orange rust.

Genetic dissection of embryo size and weight related traits for enhancement of kernel oil in maize

Embryo is a key determinant of kernel-oil in maize. Higher calorific value of maize kernel is attributed to increment in kernel-oil and it stores in specialised structure called embryo. Understanding the genetic behaviour of embryo size and weight related-traits is inevitable task for genetic improvement of kernel-oil. Here, the six-basic generations (P1, P2, F1, F2, BC1P1 and BC1P2) of three crosses (CRPBIO-962 × EC932601, CRPBIO-973 × CRPBIO-966 and CRPBIO-966 × CRPBIO-979) between contrasting embryo-sized maize inbreds were field evaluated at three locations to decipher the genetics of twenty embryo, kernel and embryo-to-kernel related-traits through generation-mean-analysis (GMA). Combined ANOVA revealed the significance of all the traits among generations; however, location and generation × location were found to be non-significant (P > 0.05) for most of the traits. Significance (P < 0.05) of scaling and joint-scaling tests revealed the presence of non-allelic interactions. Elucidation of six-parameters disclosed the predominance of dominance main-effect (h) and dominance × dominance interaction-effect (l) for most of traits. The signs of (h) and (l) indicated the prevalence of duplicate-epistasis type across crosses and locations. Thus, the population improvement approaches along with heterosis breeding method could be effective for improvement of these traits. Quantitative inheritance pattern was observed for all the traits with high broad-sense heritability and better-stability across locations. The study also predicted one to three major-gene blocks/QTLs for embryo-traits and up to 11 major-gene blocks/QTLs for embryo-to-kernel traits. These findings could provide deep insights to strategize extensive breeding methods to improve embryo traits for enhancing kernel-oil in sustainable manner.

Heritability and Genetic Advance Estimates of Key Shea Fruit Traits

Genetic erosion of shea trees, which has been on-going at an alarming rate, has necessitated urgent conservation attentions. Owing to the vast geographical distribution of the species across Ghana, in situ germplasms conservation was established by tagging and monitoring selected trees annually. Technologies have been developed that enable shea germplasms to be grafted, allowing for the development of germplasm banks at the research station of the Cocoa Research Institute of Ghana, Bole. However, before these materials could be used in crop improvement programs, there is a need to evaluate them for key fruit traits relevant to the global shea business. This experiment was carried out to evaluate the tagged in situ shea trees for fruit and nut traits. Freshly harvested shea fruits were evaluated for their brix, pulp yield and kernel size properties to see if there was the needed diversity for crop improvement gains. Eight key traits were studied, with all showing significant difference, with high broad sense heritability and genetic advance for all the traits, indicating the potential for genetic gains in breeding programs. Qualitative analysis classified the fruits into five shapes, ellipsoid fruit shape was the most frequent observation (69.5%), while oblong was the least represented (1%). Fruit surface pubescence indicated that the surfaces without hairs (smooth) were slightly higher in number (52.6%) than the surface with hairs (rough), which were 47.4%. Pearson correlation studies showed a positive significant relationship between kernel weight and fruit weight (0.68), fruit length (0.48), fruit width (0.51), pulp weight (0.5) and shell weight (0.77). Key components responsible for total variations observed were decomposed from the first two principal components (PC), which cumulatively explained 78.4% of the total observed variation within the materials. PC1 alone contributed 46.4%, while PC2 contributed 32%. Fruit weight, fruit length, fruit width, pulp weight, nut weight, shell weight and kernel weight were contributing traits to variations observed in PC1, while brix and percent pulp contributed to the variations observed in PC2. Percent kernel to nut ratio contributed to the variations observed in PC3. Clustering of the germplasms showed no regular pattern based on location or any particular trait, indicating a high level of diversity at 58% of the Pearson dissimilarity index.

Morpho-agronomic variability, traits association and path analysis in Rosemary (Salvia rosmarinus Schleid.) genotypes from Ethiopia

Forty-five rosemary genotypes collected from different parts of Ethiopia were evaluated for quantitative morphological traits to estimate the genetic variability, heritability and association of characters. The genotypes displayed significant differences for all of the studied traits, showing the presence of wide variability among the tested genotypes. The genotypic and phenotypic coefficients of variation were found to be medium and high for all growth and yield traits except for leaf length. Moderately high to high broad-sense heritability (0.66 -0.97) coupled with moderate to high genetic advance as a percent of the mean (10.37 -79.14) values were found for all traits. Correlation coefficient and path coefficient analysis revealed that characters vis. branch number plant-1, fresh leaf weight plant-1, dry leaf weight plant-1, fresh leaf yield ha-1, and essential oil content had a high positive direct effect and significant positive association with essential oil yield ha-1. Thus direct selection for these traits would be quite effective for essential oil yield enhancement in rosemary. In general, the studied accessions were diverse in nature and could be exploited in the conservation, breeding and commercialization of the crop.

English

Characterization and conservation of germplasm is a critical step toward the genetic improvement of the crop. This study assessed variation in 257 common bean genotypes which included 207 accessions obtained the National Gene Bank of Kenya, 33 accessions from Kenya Agricultural and Livestock Research Organization (KALRO), 13 landraces collected from farmers&rsquo; fields and four commercial varieties for various agronomic traits. The experiments were laid out in a randomized complete block design with three replicates at Jomo Kenyatta University of Agriculture and Technology (Kenya) for four seasons between 2019 and 2020. Significant differences (P&le;0.05) existed among the common bean accessions for all traits studied. Seed yield ranged from 220.6 to 4641.9 kg/ha (KNB0106) among the accessions with a mean of 1267.0 kg/ha. Significant (P &le;0.05) positive correlation was recorded for days to flowering and days to maturity (0.73), while 100-seed weight had a significantly negative correlation with the number of pods per plant (-0.66) and the number of seeds per pod (-0.65). High (&gt;20%) broad-sense heritability was recorded for 100-seed weight (89.0%), days to flowering (76.8%), and grain yield (60.5%). Nineteen accessions that combined early maturity and high-yielding traits were identified. On average, higher seed yields were recorded for large-seeded and climbing genotypes compared to small-seeded and bush types. Common bean accessions characterized can be exploited in breeding programs. Key words: Common bean, agronomic traits, Phaseolus vulgaris, variability, broad sense heritability.

Variability studies and genetic divergence in cotton (Gossypium hirsutum L.) germplasm using multivariate analysis

Two hundred germplasm lines of upland cotton (Gossypium hirsutum L.) were evaluated for genetic variability and divergence for seed cotton yield attributing traits and fibre quality traits at Regional Agricultural Research Station, ANGRAU, Lam, Guntur. The analysis of variance indicated significant genetic variability among the germplasm lines. The close symmetry between the phenotypic and genotypic coefficient of variances and lower values of environmental coefficient variance for all the studied attributes indicated that the traits were genetically controlled and under less influence of the environment. &nbsp;&nbsp;Higher broad sense heritability and genetic advance for all seed cotton yield attributing traits indicated that these attributes were governed by additive genes and early phenotypic selection for their improvement might be effective. Five principal components (PCs) were depicted as having Eigen value &gt;1 and cumulative variability of 66.17%, out of which PC1 accounted for 26.81% and &nbsp;PC2 &nbsp;for 14.08% of variability. The attributes of significance depicted in PC1 were seed index, lint index, upper half mean length, uniformity index, and staple length. Bi-plot revealed that Lam GPC232, Lam GPC223, Lam GPC225, Lam GPC135, Lam GPC62, Lam GPC85, Lam GPC168, and Lam GPC203 were the most divergent germplasm. These genetically diverse genotypes with the absolute and significant association of attributes could be utilized in a future cotton breeding program. Keywords: Genetic variability, Genetic advance, Heritability, PCA

Genetic Variability and Correlation Studies in Gladiolus Hybridus Hort. Under Bundelkhand Conditions

A field experiment was conducted to estimate genetic variability, heritability and correlation among the economically important characters in gladiolus varieties at the Instructional Farm, College of Horticulture, BUAT, Banda. The healthy and uniform sized corms (4 to 5 cm) were planted at a spacing of 30 × 20 cm in each row at a depth of 5-6 cm. Before planting, corms were dipped in captan (0.2%) solution for 25-30 min as a preventive measure against Fusarium wilt disease. The varieties showed significant variability (p &lt; 0.05) for days taken to spike emergence (66.67-86.69 days), days taken to opening of first floret (86.21-101.80 days), plant height (74.93 to 105.47 cm), spike length (67.07 to 89.93 cm), rachis length (33.89 to 55.64 cm), water uptake (17.33-46.67 ml), corm weight (39.97 to 100 g) and number of cormels per plant (4.47-41.97). Phenotypic coefficient of variation and genotypic coefficient of variation were high for the traits studied, except days taken to spike emergence, days taken to opening of first floret and corm diameter. High broadsense heritability value was found for number of corms per plant (90.64 %), corm weight (76.09 %) and days taken to opening of first floret, indicating the presence of additive gene effects. Positive correlation was found between days taken to spike emergence and days taken to opening of first floret (r = 0.880**); number of leaves per plant (r = 0.543*), plant height (r = 0.560*) and corm weight (r = 0.515*). Bangladesh J. Bot. 51(4): 705-712, 2022 (December)

Phenotypic diversity, heritability, and association of characters in sugarcane genotypes at Metehara Sugar Estate, Ethiopia

ABSTRACT Genetic improvement of sugarcane (Saccharum spp. hybrids) yield is crucial in the improvement of crop productivity. This study was conducted with the objectives to estimate the degree of phenotypic diversity, heritability, and association of various traits and recommend sugarcane genotypes for commercial production and small-scale farmers. Fifteen sugarcane genotypes and one standard check variety were evaluated in plant, first and second ratoon crops for 14 quantitative traits including stalk and juice quality. Highly significant (p ≤ 0.01) differences among the genotypes for all the traits were observed. Phenotypic diversity of genotypes by principal component analysis (PCA) and cluster analysis indicated genetically diverse genotypes from divergent cluster groups, which can be exploited as desirable parents to use in hybridization programs. All traits had low to high correlations (r = 0.132 to 0.719) with cane yield. High broad-sense heritability (h2) was detected for single cane weight (82.55), number of millable canes (76.85), plant height (76.79), stalk diameter (73.22), and internode length (73.69) indicating that these traits could be selected for easily. Highest expected genetic gains were recorded in single cane weight (30.12) and number of millable canes (28.6). Path coefficient analysis of cane yield revealed that single cane weight and number of millable canes were the major contributors to cane yield. Results showed that millable cane number and single cane weight can be used as reliable selection criteria to improve sugarcane yield. Genotypes FG03104, FG05414, and FG05300 can be considered for commercial production at Metehara Sugar Estate and similar agroecologies.

GENETIC VARIABILITY AND DIVERSITY OF UPLAND RICE LANDRACES

Genetic variability and diversity studies provide important data for plant breeders who manage breeding programs. Forty-three upland rice genotypes collected in Thailand were assessed genetic variability using randomized complete block designs with three replications in two years at the Faculty of Natural Resources, Prince of Songkla University. The eight characterized quantitative traits showed significant variations by genotypes. For the interaction genotype×year, significance was found in days to maturity, plant height, number of tillers hill-1, yield, and 1,000 seed weight. High genetic coefficients of variation were observed for days to flowering, plant height, number of tillers hill-1, 1,000 seed weight, and seed width. High broad-sense heritability was found for days to flowering, days to maturity, plant height, number of tillers hill-1, 1,000 seed weight, and seed width. Cluster analysis grouped the 43 genotypes into eight groups based on SSR markers at 0.752 similarity level. These results expose the broad variability and assist rice breeders in selecting the appropriate genotypes for future breeding programs.

Novel sources of drought tolerance in sorghum landraces revealed via the analyses of genotype-by-environment interactions.

Globally, sorghum is the fifth most important crop, which is used for food, feed and fuel. However, its production and productivity are severely limited by various stresses, including drought. Hence, this study aimed to determine the responses of different drought-tolerance related traits in the Ethiopian sorghum germplasm through multi-environment field trials, thereby identifying novel sources of germplasm that can be used for breeding the crop for drought-tolerance. Three hundred twenty sorghum landraces and four improved varieties were grown at three sites within drought-prone areas (Melkassa, Mieso and Mehoni) in Ethiopia. The targeted traits were chlorophyll content at flowering (CHLF), chlorophyll content at maturity (CHLM), green leaf number at flowering (GLNF), stay-green (SG), flag leaf area (FLA), peduncle length (PDL), and panicle exertion (PAE). Multi-variate analyses of the collected data revealed the presence of high phenotypic variation in all traits. The combined and AMMI Analysis of variance showed that phenotypic variation due to the genotypes was higher for SG, CHLM, CHLF and GLNF and lower for FLA, PE and PDL in comparison with variation due to the environments or genotype by environment interactions. High broad sense heritability was observed for CHLF, CHLM, SG, GLNF, FLA, and PDL, whereas PAE showed moderate heritability. Due to the high heritability of chlorophyll content and the relatively small effect of environmental factors on it, it could serve as a criterion for selecting desirable genotypes for drought-tolerant breeding in sorghum. It has been found that chlorophyll content has a significant positive correlation with stay-green and grain yield, indicating that high chlorophyll content contributes to increasing grain yield by delaying the process of leaf senescence. The analyses of AMMI, GGE biplot, and genotype selection index revealed that several sorghum landraces outperformed the improved varieties with respect to CHLF, CHLM, and SG. Such landraces could serve as novel sources of germplasm for improving drought tolerance through breeding.