Promising Landraces Research Articles

Efficacy of different rhizobia strains with specific common beans landraces in biological nitrogen fixation

Bean production in Tanzania barely meets half of the domestic demand because of low yield attributed to low fertility, nitrogen being the most common deficient. The use of rhizobia inoculants can substantially increase bean yields. However, less than 1% of the farming population is aware of inoculants. The aim of the study was to evaluate the efficacy of different rhizobia strains with specific common beans landraces in biological nitrogen fixation and yields. Four experiments were conducted during in a screen house at Sokoine University of Agriculture (SUA). Two experiment consisted Leonard jar and the other two were pot experiments in which the soil used were either sterilized or unsterilized. The landraces collected were Kasuka Nywele, Msafiri and Manjano from Mbeya; Nyayo, Soya and Kachumbaa from Arusha; and Kabungu, Nyamungu and Karanga from Morogoro. Two sets of Leonard jars were arranged in completely randomized block design in triplicate and the other two pot experiments were arranged in split split plot design. Inoculants in pot experiments used were Nitro-SUA, Underwood Biostacked as commercial and native. Landrace were the main plot, soil sterilization as a sub plot and inoculants as sub sub plot replicated three times. Data were subjected to analysis of variance using GENSTAT software. Significance differences in N2 fixation were observed among all landraces in all experiments, promising results were observed from Nyayo, Nyamungu, Msafiri and Kabungu. Native rhizobia had comparable symbiotic effectiveness to commercial inoculants in unsterilized soils and vice versa in sterilized soils conditions though soil sterilization was not significant. The findings on this study provide rooms for further research especially on the promising landraces to nodulation and explore their effectiveness.

Genotyping of DNA pools identifies untapped landraces and genomic regions to develop next-generation varieties.

Landraces, that is, traditional varieties, have a large diversity that is underexploited in modern breeding. A novel DNA pooling strategy was implemented to identify promising landraces and genomic regions to enlarge the genetic diversity of modern varieties. As proof of concept, DNA pools from 156 American and European maize landraces representing 2340 individuals were genotyped with an SNP array to assess their genome-wide diversity. They were compared to elite cultivars produced across the 20th century, represented by 327 inbred lines. Detection of selective footprints between landraces of different geographic origin identified genes involved in environmental adaptation (flowering times, growth) and tolerance to abiotic and biotic stress (drought, cold, salinity). Promising landraces were identified by developing two novel indicators that estimate their contribution to the genome of inbred lines: (i) a modified Roger's distance standardized by gene diversity and (ii) the assignation of lines to landraces using supervised analysis. It showed that most landraces do not have closely related lines and that only 10 landraces, including famous landraces as Reid's Yellow Dent, Lancaster Surecrop and Lacaune, cumulated half of the total contribution to inbred lines. Comparison of ancestral lines directly derived from landraces with lines from more advanced breeding cycles showed a decrease in the number of landraces with a large contribution. New inbred lines derived from landraces with limited contributions enriched more the haplotype diversity of reference inbred lines than those with a high contribution. Our approach opens an avenue for the identification of promising landraces for pre-breeding.

A Preliminary Evaluation of Variability, Genetic Estimates, and Association among Phenotypic Traits of African Yam Bean Landraces from Ghana

A field experiment was conducted at the Research and Teaching Farm, School of Agriculture and Technology (SOAT), University of Energy and Natural Resources (UENR), Dormaa Ahenkro Campus, Ghana, to determine the genetic variability, heritability, genetic advance, and correlation among growth and yield traits of the African yam bean in Ghana. There were significant differences ( p < 0.05 ) for the traits studied, except for days to 50% emergence, petiole length, days to maturity, stem diameter, days to 50% flowering, pod weight, pod beak length, pod weight per plant, seed length, and seed width. The phenotypic coefficient of variation and genotypic coefficient of variation for the yield and yield components ranged from 9.43% to 18.92% and 3.25% to 15.93%, respectively, and from 9.35% to 20.08% and 2.15% to 23.28%, respectively, for the growth parameters. Heritability ranged from 34.54% to 91.81, and the GAM ranged from 2.77% to 45.96% for the growth parameters. The heritability and GAM for the yield parameters ranged from 11.85% to 73.56% and 1.94% to 27.64%, respectively. The correlation analysis revealed a positive and highly significant ( p < 0.001 ) relationship between petiole length and leaf length (r = 0.573), number of seeds per pod and number of leaves (r = 0.520), pod beak length and peduncle length (r = 0.560), pod weight per plant and pod weight per plot (r = 0.971), seed weight per plant and 100 seed weight (r = 0.967), grain yield and 100 seed weight (r = 0.999) and seed weight per plant (r = 0.970), 100 seed weight and pod per plant (r = 0.576). The study revealed diversity among the AYB landraces collected, which provides an opportunity for improvement of the African yam bean in Ghana. There is the need for the conservation of these landraces for further evaluations and the improvement of the promising landraces and traits through breeding programmes.

Acclimatization of non-cultivated rice landraces to early moisture stress mediated by enzymatic antioxidants and osmolyte accumulation

Moisture stress affects the physiological and biochemical characteristics of plants such as the propensity for cellular water, induces stomatal closure, and reduces photosynthetic capacity, nitrate assimilation and substantial anabolic metabolism. In this study we assessed the antioxidative enzymes and osmolyte accumulation of fifty traditional non-cultivated rice landraces from Tamil Nadu, India. Artificial moisture stress was imposed in a hydroponic setup with maximum osmotic potential of (−) 15 bars. On the basis of drought and leaf rolling scores at 26 d, thirteen landraces were carried forward for further studies. The root/shoot ratio (R/S) was also significant for the selected landraces against IR64 as drought-susceptible check. The genotypes Kuliyadichan, Chandaikar, Mallikar, Nootripathu and Rajalakshmi were able to withstand intense moisture stress at 26 d with a score of 0 and 1, according to standard evaluation system for rice. Photosynthetic pigment and proline content of the above landraces increased during moisture stress in accordance with the positive check IR 64 (Drt1), however differential responses observed in all the landraces. Enzymatic antioxidant markers such as superoxide dismutase, catalase and peroxidase in shoots of all the selected landraces were greater than IR 64 (Drt1), under moisture stress. We identified Kuliyadichan, Rajalakshmi and Nootripathu as promising landraces with substantial moisture stress tolerance. Further, a positive correlation between overall seedling development and antioxidant enzymes as well as proline accumulation was observed under moisture stress. The mechanisms governing drought tolerance/avoidance in these moisture stress tolerant rice landraces might be attributed to active antioxidant defense system and proline accumulation for alleviating induced oxidative stress. Thus, the identified non-cultivated traditional rice landraces may be employed as potential donors for rice improvement programme towards climate resilience.

Characterization and evaluation of Greek tomato landraces for productivity and fruit quality traits related to sustainable low-input farming systems.

Tomato is one of the most important horticultural species all over the world, having high level of consumption and employing many people, both in the primary sector (farmers) and in the secondary sector (traders, seed companies and processors). Nowadays, the use of commercial tomato F1 hybrids tends to prevail because of high yield potential and homogeneity of fruits which are often characterized by lack of quality and sensory characteristics. In contrast, tomato landraces have outstanding quality traits, such as high concentration of antioxidants and organoleptic compounds, as well as often include desirable genes in their genome for adaptability, plasticity, response to low-input conditions, and high fruit nutritional value. Thus, they are appropriate material in the use of sustainable agricultural management systems or as gene donors for the development of new type of tomato cultivars suitable for low-input farming systems. The present experimental study refers to 22 Greek tomato landraces and two commercial cultivars (cv. Macedonia and the F1 hybrid Formula) used as controls, which were characterized by phenotypical markers and evaluated under low-input sustainable farming conditions. Specifically, during this research, measurements were taken regarding yield potential (early production, number of fruits per plant, fruit weight, total yield) and fruit quality traits, such as physicochemical characteristics (pH, acidity, and soluble solid components - Brixο) also according to nutritional value (content of ascorbic acid, lycopene, total carotenoids, and total phenolics) of tomato fruits. In the most promising landraces (cv. Milo Chalkidiki, cv. Eratiras, cv. Lotos, cv. Aspros lotos, cv. Pantaroza, cv. Karabola and cv. Kardia Vodiou), having comparable yield and fruit quality traits with commercial cultivars, intrapopulation "Pure line selection" method, under low-input farming conditions was applied for two years. Following this approach, we succeed to determine the level of yield potential and provide information for the nutritive value and utilization of typical tomato landraces, improving their yield and fruit quality traits, following a mild intrapopulation selection under low-input farming conditions. This data pipeline is expected to be of interest for organic farmers and processors of high nutritive tomato products, with low carbon footprint for the environment.

Multi-Environment Screening of Nepalese Finger Millet Landraces against Blast Disease [Pyricularia grisea (Cooke) Sacc.)

Three hundred finger millet genotypes (295 landraces from 54 districts and five released varieties) were evaluated for leaf, finger, and neck blast resistance under natural epiphytotic conditions across three hill locations in Nepal, namely Kabre, Dolakha (1740m); Vijaynagar, Jumla (2350 m); and Khumaltar, Lalitpur (1360 m) during the summer seasons of 2017 and 2018. The highest incidence of leaf, neck, and finger blast was observed at Lalitpur, followed by Dolakha and Jumla, whereas the overall disease incidence was higher in 2018 compared to 2017. Combined analysis over environments revealed non-significant differences among accessions for leaf blast, but the difference was highly significant for neck and finger blast. Correlation analysis suggested that there was a strong positive correlation between neck blast and finger blast (r = 0.71), leaf blast (seedling stage) and neck blast (r = 0.68), and leaf blast (seedling stage) and finger blast (r = 0.58) diseases. Among 300 accessions, 95 had lower scores for finger blast, 30 for neck blast, and 74 for leaf blast than the score of Kabre Kodo-2, the latest released variety in Nepal. Genotypes NGRC04798, NGRC03478, NGRC05765, NGRC03539, NGRC06484, NGRC01458, NGRC01495 and NGRC01597 were found the resistant genotypes for finger blast (2.1-2.3) and neck blast (1.5-2.3) based on pooled mean scores. This study shows the variable reactions of finger millet genotypes against blast disease in various environments and reports the promising landraces having field resistance to leaf, finger, and neck blast, which ultimately serve as important donors for blast resistance in finger millet breeding.

Study on physicochemical properties of rice landraces for amylose, gel consistency and gelatinization temperature

Rice grain quality depends on physical, biochemical, cooking quality and organoleptic characters. Grain quality analysis in rice involves a physicochemical and sensory tests. In this study, morphologically different 60 rice landraces of Tamil Nadu along with ADT (R) 45 as a check variety were used for physicochemical analysis based on the amylose content (AC), gel consistency (GC) and gelatinization temperature (GT). Highly significant variation (p<0.05) was observed among the 60 landraces for all the characters. Most of the landraces registered low amylose content. Nine landraces exhibited high and 18 landraces exhibited intermediate AC. In the case of a gel consistency, most of the landraces exhibited soft GC, while four landraces viz., Athur kichadi, Kavuni nel, Uppu mulagai and Valan registered medium gel. With respect to GT, all the landraces exhibited high to intermediate GT except Kattu ponni, Kavuni nel and Sugandni samba which were identified with low GT. The check variety exhibited intermediate amylose, soft gel and high gelatinization temperature. The landraces Chennellu, Kattu vanipam, Kichali samba, Kuttala samba, Pome, Revathi, Samba masanam, Saysree, Sembalai, Sivappu Kavuni, Soora kuruvai, Thailand Kavuni, Thanga samba and Thirupathisaram were identified as promising landraces based on intermediate amylose, soft gel consistency and intermediate gelatinization temperature. High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) coupled with high heritability and high genetic advance as a percentage of mean were recorded in all three characters indicating additive gene action. This indicates that there was a low environmental influence on the expression of these characters and hence one can practice selection. The results of this study provide vital information on amylose content gel consistency and gelatinization temperature of various rice landraces which can be utilized in a breeding programme directed towards improving the cooking and eating quality. Landraces with high amylose content can be further studied for identifying landraces with high resistant starch and low Glycaemic Index. Key words: Amylose content, Gel consistency, Gelatinization temperature, landraces, rice

Seedling and Adult Plant Resistance in the Ethiopian Bread Wheat Landraces to Stripe Rust Disease

High yielding farmers’ bread wheat cultivars are threatened by emerging race(s) of stripe (yellow) rust caused by Puccinia striiformis f.sp. tritici (Pst) in the highlands of Ethiopia. In depletion of rust resistance in commercial cultivars, researchers often look for new sources from close relatives and landraces. The objective of this study was to determine stripe rust resistance in selected Ethiopian bread wheat landraces obtained from the Ethiopian Institute of Biodiversity (IBCE). In 2017, a total of 152 accessions were exposed to the prevailing stripe rust races in hot spot areas (Kulumsa and Meraro) in Arsi zone of Oromia region. In the second year (2018), only promising landraces (57) were evaluated both at seedling and adult plant growth stages. The seedling test was conducted in the greenhouse at Kulumsa research center using three (PstS2 (v32), (PstS11) and (PstS11 v25) Pst races. In field evaluations, terminal severity (TRS), coefficient of infection (CI), area under disease progress curve (AUDPC), disease progress rate (DPR) and head infection (HI) were considred. High disease pressure was noted with 100% severity on susceptible entries at both locations and seasons. Highly significant (P<0.001) differences were noted among the landraces for all disease parameters indicated above. Of the 152 landraces, 57(38%) exhibited lower or equal disease reaction compared to the resistant check(Enkoy) across locations. Overall, 18 accessions showed resistance to the prevailing Pst races both at seedling stage and field conditions whereas14 exhibited susceptible /intermediate reaction at seedling stage, but had lower disease reaction under field conditions. This study has identified potential sources of overall and adult plant resistance in the Ethiopian bread wheat landraces to the prevailing Pst races. The authors recommend further studies to determine the diversity and/or novelity of resistance genes in selected accessions. Future wheat improvement should focus on utilization of these genetic resources to minimize the re-current outbreak of rust diseases.

Identification of Stripe Rust (Puccinia striiformis F. sp. Tritici) Resistance in the Ethiopian Wheat Landraces

Stripe rust is caused by Puccinia striiformis f. sp. tritici (Pst) is threatening wheat production in Ethiopia. Wheat varieties succumb to new Pst race (s) soon after their release from research centers. The objective of this study was to determine stripe rust resistance in selected Ethiopian wheat landraces obtained from the Ethiopian Institute of Biodiversity (IBCE). In 2017, a total of 197 accessions (152 bread and 45 durum wheat land-races) were exposed to the prevailing stripe rust races in hot spot areas (Kulumsa and Meraro) in Arsi zone of Oromia region. In the second year 2018, only promising landraces 103 (69 bread and 34 durum)) were evaluated both at seedling and adult plant growth stages. The seedling test was conducted in the greenhouse at Kulumsa research center using three Pstraces. In field evaluations, terminal severity (TRS), coefficient of infection (CI), area under disease progress curve (AUDPC), disease progress rate (DPR) and spike infection (SI) were considered. High disease pressure was noted with 100% severity on susceptible entries at both locations and seasons. Highly significant (P<0.001) differences were noted among the landraces for all disease parameters indicated above. Of the 103 landraces, 57 (55%) exhibited lower or equal disease reaction compared to the resistant check (Enkoy) across locations and seasons. Thirty two landraces showed both adult plant and seedling resistance. The 103 Ethiopian wheat landraces that showed field resistance further exposed to three Pst races at seedling stage and 61 exhibited seedling resistance to all races. This study has identified potential sources of seedling and adult plant resistance in the Ethiopian wheat landraces to the prevailing Pst races. Future wheat improvement should focus on utilization of these genetic resources to minimize the re-current outbreak of rust diseases.

Screening Turkish maize landraces for kernel oil content and oil quality traits

AbstractIn this study, maize landraces, previously collected from different regions of Turkey through a national maize breeding project, were screened for kernel oil content and oil quality. After a seed reproduction in 2017, the screening trial was conducted in 2018, using an Augmented Experimental Design with 192 local maize populations along with seven check hybrids. Data were collected on oil, oleic acid, linoleic acid, monounsaturated (MUFA), polyunsaturated and saturated fatty acids, total carotenoid and total tocopherol contents. The results showed that there was a considerable amount of genetic variation among the Turkish maize landraces for almost all the traits investigated in this study. Some of the evaluated landraces are available that could be considered as high oil variety or special genotypes in terms of certain oil quality traits. Landraces had significantly higher values than checks for oil content, oleic acid, MUFA and tocopherol contents. Genetic analyses suggest that the kernel quality traits could be successfully manipulated using the investigated plant material. Heritability values were found high for all the traits of interest, except for saturated fatty acid and total carotenoid content. The promising landraces detected in this study could be exploited in future breeding programmes upon further evaluations at the population level.

Genetic variation in some Iranian bitter vetch (Vicia ervilia L.) landraces based on agronomic-morphological traits for use in breeding program in Rafsanjan

The aims of this research were to generate information on agro-morphological variability among 42 bitter vetch (Vicia ervilia L.) landraces collected from major growing areas of North West of Iran. The landraces were grown according to rectangular lattice design in the field across 2 years (2018 and 2019) in the Research Farm at Vali-e-Asr University of Rafsanjan (Rafsanjan, Iran). Observations were recorded days to 50% flowering, days to maturing start, days to 50% maturing, height to first flower node, plant height in flowering stage, plant height in maturity stage, root length in maturity stage, number of lateral branch, one, two and three seed pod length, number of pod per plant, number of seed per pod, number of seed per plant, thousand kernel weight, biomass and grain yield. Analysis of variance revealed significant variation among landraces for the majority of the traits. Using principal component analysis, the first five PCs with eigenvalues > 1 contributed 74.4% of the variability among landraces. PC1, which is the most important component, explained 28. 9% of the total variation and was positively related to days to 50% maturing, plant height in maturity stage, days to maturing start, plant height in flowering stage, height to first flower node and biomass, respectively and PC2 accounted for 20.6% of the total variation and the traits with the greatest weight on this component were number of seed per plant, number of pod per plant, grain yield and two seed pod length, respectively. Cluster analysis using Ward method divided landraces into four groups. Based on cluster analysis and mean comparison among four groups, promising landraces were identified with superior traits such as number of pod per plant, number of seed per plant, thousand kernel weight, biomass and grain yield. The results demonstrated bitter vetch landraces of North West of Iran are a useful source of diversity in desirable traits that can be exploited in future breeding programs.

Agro-morphological characterization of rice (Oryza sativa L.) landraces of Lamjung and Tanahun District, Nepal.

Agro-morphological characterization of crop is the basic criteria to provide fundamental information for plant breeding programs. An investigation was conducted in Agronomy farm of Institute of Agriculture and Animal Science, Lamjung Campus in alpha-lattice design with two replications. The objective of the study was to characterize thirty landraces of rice ( Oryza sativa L.) of Lamjung and Tanahun district based on 30 qualitative and 8 quantitative characters, recorded as per descriptor established by IRRI, Bioversity International and WARDA. The frequency distribution of qualitative characters were studied where panicle shattering, lemma & palea color, culm lodging resistance and Leaf senescence showed high variability. The maximum value, minimum value, coefficient of variation and Pearson correlation were analyzed to study quantitative characters. The coefficient of variation ranged from 5.4% (Grain Length: Breadth ratio) to 20% (Total Tillers) indicating that selection based on the characters showing higher variation is expected to be effective. The highest correlation was corresponded to the total tillers and effective tillers (r=0.978 ** ). Flag leaf length showed positive significant correlation with penultimate leaf length (r=0.674 ** ), total tillers (r=0.437 ** ), effective tillers (r=0.356 ** ) and Grain Length: Breadth ratio (r=0.430 ** ). UPGMA clustering of the genotypes was done where members of cluster IV were found to be more superior. Promising landraces were identified from different yield attributing characters like total tillers, total grains per panicle, 1000 grain weight, panicle length and filled grain percentage. Thus, the present study can be utilized for further rice improvement programs and can also be used for assessing genetic diversity among morphologically distinguishable rice landraces.

Characterization of Rice Landraces from Dibrugarh District of Assam

Twenty five different traditional rice landraces from Dibrugarh district of Assam were characterized. In case of morphological characters, high heritability coupled with high genetic advance was recorded for number of grains per plant and number of panicle per plant. For biochemical parameters, high heritability coupled with high genetic advance was recorded for amylose and fat contents. Correlation coefficient analysis revealed that number of grains per plant, plant height, stem length and panicle length exhibited positive correlation with grain yield per plant. Thus, stem length and numbers of grains per plant can be considered in breeding programme. The landraces were with low to intermediate gelatinization temperature range (55–74 oC) indicating good cooking quality. The study identified Kolajoha, Miatong, Bor Aijung, Ronga Bordhan, Bor Salpona, Dolkochi, and Athabora as promising landraces that could be utilized in the development of high yielding landraces.

Genetic Divergence Among Post-rainy Season-Grown Sorghum Local Landraces and Varieties for Morphological and Yield Traits

Post-rainy season-cultivated sorghum lines are local landraces, known for their grain quality and used exclusively for human consumption. Because of their importance, the present study was undertaken to estimate genetic diversity for morphological and yield-contributing traits at two locations. The ANOVA for days to flower, stem diameter, panicle width, yield per plant and 100 seed weight showed significant differences among 85 sorghum landraces and 15 popular varieties. Mean squares for all the traits were significantly affected by genotypes (G), environments (E) and G × E interaction. Relatively high broad-sense heritability was observed for grain yield at BARC, Mumbai (E1), and panicle length at ARS, Gulbarga (E2) locations, respectively. Significant positive correlations between panicle width and grain yield (0.23**) and between seed weight and grain yield (0.22**) were observed. Cluster analysis based on Euclidean distance grouped all the genotypes into five clusters with PC-6 emerging as a distinct variety. Promising landraces identified in this study would serve as genetic resources for recombination breeding.

Evaluation of water-deficit stress tolerance in Bambara groundnut landraces for cultivation in sub-tropical environments in India

In the perspective of climate change scenario, resilient crops are essential for future cultivation. Bambara groundnut (Vigna subterranea L. Verdc.) is legume and well known for its drought tolerance, mainly cultivated in Africa. This study was under taken to evaluate Bambara groundnut landraces for pod and biomass yields. Promising landraces were analysed for drought tolerance under fully irrigated (IR100), 50% water cut (IR50) and progressive water-deficit stress for 6 days (IR0) in pot culture experiment. Wide variations were recorded in leaf chlorophyll and carotenoid, chlorophyll a fluorescence, relative water content, water potential, proline, epicuticular wax load, vegetative growth and pod yields, under different soil moisture regimes. Drought tolerant landraces were able to maintain leaf-water-relation traits and photosynthetic efficiency under both IR50 and IR0. Such as, slopes between relative water content and depleting soil moisture in IR0 were higher in SB 4-2 (3.5) and Uniswa Red (2.6) and, lower in DodR Tz (2.0) and S 19-3 (1.9). Also, leaf epicuticular wax load showed different patterns both in its inherent and acquired potential, for example, inherent potential was lower and acquired higher in SB 4-2, while inherent potential was higher and acquired lower in S 19-3. Under normal irrigation, pod and biomass yields were higher in DodR Tz and SB 4-2 whereas reduction in pod and biomass yields were lower in S 19-3 and DodR Tz, under water-deficit. Variations in all characters studied were significantly (P < 0.01) influenced by landrace, suggesting a strong genetic basis for the phenotypic differences amongst landraces. Thus, characteristics of S 19-3 in drought tolerance and SB 4-2 in higher biomass in IR100 could be used for improving drought tolerance for different water scarcity environments, world-wide.

Tapping the genetic diversity of landraces in allogamous crops with doubled haploid lines: a case study from European flint maize.

Using landraces for broadening the genetic base of elite maize germplasm is hampered by heterogeneity and high genetic load. Production of DH line libraries can help to overcome these problems. Landraces of maize (Zea mays L.) represent a huge reservoir of genetic diversity largely untapped by breeders. Genetic heterogeneity and a high genetic load hamper their use in hybrid breeding. Production of doubled haploid line libraries (DHL) by the in vivo haploid induction method promises to overcome these problems. To test this hypothesis, we compared the line per se performance of 389 doubled haploid (DH) lines across six DHL produced from European flint landraces with that of four flint founder lines (FFL) and 53 elite flint lines (EFL) for 16 agronomic traits evaluated in four locations. The genotypic variance ([Formula: see text]) within DHL was generally much larger than that among DHL and exceeded also[Formula: see text] of the EFL. For most traits, the means and [Formula: see text] differed considerably among the DHL, resulting in different expected selection gains. Mean grain yield of the EFL was 25 and 62% higher than for the FFL and DHL, respectively, indicating considerable breeding progress in the EFL and a remnant genetic load in the DHL. Usefulness of the best 20% lines was for individual DHL comparable to the EFL and grain yield (GY) in the top lines from both groups was similar. Our results corroborate the tremendous potential of landraces for broadening the narrow genetic base of elite germplasm. To make best use of these "gold reserves", we propose a multi-stage selection approach with optimal allocation of resources to (1) choose the most promising landraces for DHL production and (2) identify the top DH lines for further breeding.

Genetic Analysis of Cadmium Accumulation in Shoots of Sorghum Landraces

Contamination of agricultural fields with heavy metals, such as Cd, is a serious issue for safe food production worldwide. Previous reports indicate that sorghum [Sorghum bicolor (L.) Moench] is useful for phytoextraction of Cd from contaminated soils. To investigate the diversity for Cd accumulation in sorghum germplasm and to select useful cultivars for phytoextraction, we conducted experiments using 106 sorghum landraces and the cultivar BTx623, grown in hydroponic cultures and under field conditions. The Cd concentrations in plant shoots of different landraces showed no correlation between hydroponic and field‐grown plants (r = −0.16). We measured Cd concentrations in various plant parts at different stages of development in field‐grown plants and found that leaf sheaths often had higher Cd concentrations than other plant parts. Our results indicated that screening could be done for plants that might be useful for phytoextraction of Cd by determining the Cd concentrations in leaf sheaths of 1‐mo‐old plants grown in a Cd‐contaminated soil. We also mapped the quantitative trait loci (QTLs) responsible for Cd accumulation in sorghum shoots and found several chromosomal regions that affected Cd concentrations in different parts of the shoot. We were able to identify several promising landraces for developing sorghum cultivars that are capable of accumulating high levels of Cd and phytoextracting Cd from contaminated soils.

Selection criteria for grain yield and stability in bambara groundnut (Vigna subterranean (L) Verdc) landraces

The potential of bambara groundnut as a crop-based approach for the sustainable reduction of protein–energy malnutrition prevalent in Nigeria is still being explored. However, one of the limitations to sustainable production of this adapted species is low and unstable yield. Here, we employed multiple statistical analyses to determine traits that could be useful in predicting grain yield. Furthermore, additive main effect and multiplicative interaction and genotype × genotype × environment models were used to identify high yielding and stable landraces. Twenty-four bambara landraces were evaluated in two contrasting dry land growing seasons at four environments. Based on the results of correlation, path coefficient values and stepwise multiple regression analysis, it is reasonable to assume that seed growth rate would be effective as indirect selection criteria for grain yield improvement in this set of breeding materials under early and late planting environment. However, optimizing biomass growth rate, pod fill period, 100-seed weight, number of pods per plant and time to flowering may have important role in the improvement of grain yield in bambara groundnut. Due consideration should be given to 100-seed weight and time to flowering in the early dry and late planting environment. The possibility of successful cultivation of bambara groundnut in forest–savannah transition agricultural zone of Nigeria, particularly when planting is done around early August has been established in this study. However, based on the strong association between seed yield and its related characters in early and late planting environments, selection for higher seed growth rate combined with large number of pods appears to be the best indirect traits when selecting bambara groundnut plants to enhance grain yield under early and late planting environments. While landraces TVSu 1520 and 1578 were considered the best adapted landraces, TVSu 1670 and 1518 are promising landraces that could contribute to increasing grain yield stability.

A Study on Variability of Elite Landraces of Small Cardamom (Elettaria cardamomumMaton)

Even though over one dozen improved varieties of small cardamom are made available to farmers, many farmers still depend on promising landraces for cultivation. Being a crop that is mainly propagated clonally by suckers, evaluation of such landraces in order to select promising genotypes from them has immense scope in the crop improvement of cardamom. With this objective, a field experiment for the evaluation of ten elite landraces of cardamom based on genetic variability, heritability and genetic advance was undertaken. Sixty-three characters including seven growth characters, nine yield characters, sixteen quality characters and thirty-one biophysical/chemical characters were recorded. Among the growth characters, highest GCV and PCV were shown by tillers per clump; highest heritability was shown by leaf length and highest genetic advance by tillers per clump. This shows that number of tillers per clump is the most important growth character. Among the yield characters highest GCV and genetic advance were shown by internodal length, PCV by panicles per clump and heritability by racemes per panicle. In quality characters, GCV and PCV were the highest in dry seed weight and heritability in percentage of 7 mm and above sized capsules which is a very desirable phenomenon. With regard to the biophysical/biochemical characters, acid insoluble ash showed the highest GCV; PCV was shown by chlorophyll b content of leaf; heritability by acid insoluble ash in capsule. The characters analyzed showed genetic advance ranging from 0.006 to 0.58. Characters with high genetic advance could be utilized for selection.

Breeding Potential of European Flint Maize Landraces Evaluated by their Testcross Performance

ABSTRACTA plethora of maize (Zea mays L.) landraces is stored in gene banks worldwide. However, information about their value in breeding is scarce and strategies for identifying the most promising landraces in prebreeding are largely lacking. This study was conducted to (i) evaluate the testcross performance of 70 European flint landraces in combination with two elite dent testers and compare these results with the performance of modern hybrids for important agronomic traits, (ii) estimate the genetic variances among landraces and trait correlations for these two testcross series as well as the correlation between them, and (iii) devise a testing scheme for assessing the breeding potential of a large number of landraces for hybrid breeding. Grain yield of the landrace testcrosses was on average about 26% lower than modern hybrids. Genotypic variances among landrace testcrosses were significant for all traits, and genetic correlations were moderate to high for most trait combinations in both testcross series. Thus, it seems promising to tap this huge genetic reserve for enlarging the genetic base of the elite flint germplasm pool in Central Europe. Since the genetic correlation between the two testcross series exceeded 0.74 for all traits, we recommend assessing the breeding potential of landraces for broadening existing heterotic groups by evaluating their testcross performance in combination with one or two elite single‐cross tester(s) from the opposite heterotic pool. Subsequently, doubled haploid lines from a few of the most promising landraces could be produced to exploit the large genetic variation within landraces to the full extent.