A New Approach to Select Doubled Haploid Rice Lines under Salinity Stress Using Indirect Selection Index

This study determined the indirect selection index of doubled haploid(DH)rice using a multivariate analysis approach to select lines adaptive to salinity stress,comprising three experiments.The first experiment involved the selection of good agronomic characters in a field experiment conducted at an experimental station in Bogor,Indonesia.The second experiment involved salinity tolerance screening through hydroponic cultures using 0 and 120 mmol/L NaCl,conducted at a greenhouse in Bogor.The third experiment involved the validation of the indirect adaptability selection index(IASI)through a field experiment in Sukra(saline area).Field experiments followed a randomized complete block design(RCBD),whereas an RCBD nested factorial design was used for the greenhouse experiment.The first and second experiments used 56 DH lines and four check varieties with three replications.In the second experiment,Pokkali and IR29 varieties were also added as tolerant and sensitive checks of salinity,respectively.The third experiment used 28 selected DH lines,Inpari 29 and one sensitive DH line.The good agronomic index(GAI)was 0.465 yield+0.433 number of productive tillers+0.31 number of filled grains.This generated 24 DH rice lines with good agronomic traits.The salinity tolerance index(SaTI)was developed through the average of standardized salinity tolerance score and salinity selection index based on discriminant analysis.This generated 34 DH rice lines with good salinity stress tolerance.The IASI(IASI=GAI–SaTI)selected 28 DH rice lines adaptive to salinity stress and it was considered effective by Sukra validation.

Screen House Assessment of Cowpea [(Vigna unguiculata (L.)] Genotypes for Drought Tolerance Using Selection Indices

Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food security. The potential of cowpea to address food security is well established. However, not much is known about the base index selection method in breeding cowpea for drought tolerance, which is important for yields. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition, 2) ranke genotype performance using selection indices, and 3) assess relationship between agronomic traits and yield. The experiment was the 2 watering conditions laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in pots under screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, Nketewade, Ghana Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% and 16% for grain and fodder yield respectively. The biplot displays revealed four groups among the genotypes tested which were based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B were best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana Shoba. These genotypes might be suitably employed in further drought tolerance breeding programs of cowpea. Significant relationships were observed between agronomic trait and yields under drought condition.

Selection of Maize Genotypes with Tolerance to Osmotic Stress Associated with Salinity

Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effective strategy to overcome the saline stress. Osmotic stress reduces immediately the expansion of the roots and young leaves which determine a reduction in the size of the plant. A completely randomized design was adopted to test seedlings under controlled conditions of light and temperature. Two treatments were used: 0 mM NaCl (as control) and 100 mM NaCl. After 15 days of complete salinization, the seedlings were harvested and several morphological traits were measured. The morphological traits of growth were leaf growth (Ar1, Ar2, Ar3 and Ar4), dry masses of shoot and root (SDM and RDM, respectively). Also, traits associated with water economy were registered: leaf water loss (LWL) and relative water content (RWC). The morphological traits were expressed in relative terms, while the traits associated with the economy of water were expressed in absolute terms. Uni and multivariate techniques were applied to identify genotypes with divergent behaviors to osmotic stress tolerance. Also, a Tolerance Index was employed to identify superior genotypes. Four clusters were obtained after applying a Cluster Analysis and Principal Component Analysis (PCA). The genotypes were compared to each other with a test of DMS. The results obtained with different statistical techniques converged. Some variables presented a differential weight classification of genotypes. The morphological traits like RDM, SDM, Ar3, Ar4 and Ar5 were the most discriminating. Tolerance Index allowed to classify genotypes, thus SC2 and AD3 lines were that reached highest value of the index and therefore would be tolerant lines, while AF3 and LP3 had a low index and were seen as sensible.

Combined Selection in Backcross Population of Papaya(Carica papaya L.)by the Mixed Model Methodology

The selection of superior genotypes based on the simultaneous response to several characteristics of agronomic importance is a key strategy to overcome the scarcity of available varieties of papaya. This study aimed to apply the combined selection by using distinct selection indexes based on both the genetic values obtained by the REML/BLUP methodology and the real measured values to select agronomically superior genotypes of papaya within backcross progenies. The combined selection was carried out based on genetic and phenotypic values, original and standardized, multiplied by the agronomic weights. The results of the analysis of genetic parameters indicate that the evaluated progenies have expressive genetic variability for the considered traits, and that there are real possibilities of genetic progress with the selection. Among the analyzed indexes, the one based on standardized genetic value presented greater consistency in the ranking of genetic material, demonstrating the advantage of data standardization. Five progenies belonging to the BC1 generation, and five to the BC3 generation were selected using this index. A total of 27 plants ag-ronomically superior were selected within the top five progenies and recommended for generation advance, 23 being selected by combined selection and 4 using the direct selection for the four mainly characters in papaya breeding program: production, pulp and fruit firmness and soluble solids. Beyond the selection of superior genotypes for the development of future inbred lines, this study also allowed defining the best strategy to apply the combined selection in papaya using pre-dicted breeding values obtained by BLUP. This strategy may allow higher accuracy in the selection process, thus increasing the chances of success of the breeding programs.

Summer habitat selection and impacts of human disturbance on leopard cats(Prionailurus bengalensis)

Introduction:As a consequence of habitat loss and degradation,the leopard cat(Prionailurus bengalensis)in China has become endangered and in need of urgent protection.In situ conservation of leopard cats must be based on an understanding of their habitat selection patterns.We studied the summer habitat of leopard cats using line-transect surveys in the northern Taihang Mountain region surrounding Beijing,China.We compared used plots with non-used plots in elevation,tree canopy,and 20 other ecological variables,and used VanderploegScavia’s resource selection index(VSI)to analyze habitat preferences.Outcomes/others:Results show that tree canopy,tree height,tree density,and stump quantity of used plots were significantly lower than non-used plots in summer,and that leopard cats preferred habitats located on northern,flat slopes with lower slope,shrub-dominated,dry soil,and less fallen-wood.Leopard cats had a strong tendency to use habitats near human disturbance areas with moderate levels of disturbance intensity.Conclusion:The results suggest that future conservation efforts should emphasize:(1)strengthening the protection and management of forest fringe shrub habitats to improve summer habitat suitability,and(2)environmental education and animal protection campaigns to promote community biodiversity conservation.