Geometric Mean Productivity Indices Research Articles

Indicators for evaluating the resistance of tomato genotypes to low light

ABSTRACT Low light is one of the most important factors limiting tomato (Solanum lycopersicum L.) production. In this experiment, tomato genotypes under low light (winter planting), and adequate light (summer planting) were evaluated in the same greenhouse condition for other environmental conditions where 11 tolerance and susceptibility indices were evaluated in terms of fruit weight per plant produced. Using the rank of each genotype for the calculated indices, the mean rank index was calculated. The highest yield under adequate light was in genotypes “9318,” “9314,” “2216,” “324,” and “5239.” Under low light, genotypes “321,” “9318,” “9314,” “523,” and “324” had the highest fruit yield per plant, respectively. Evaluation of tolerance and sensitivity indices indicated that tolerance indices, geometric mean productivity index, mean relative performance index and relative efficiency index had a positive, significant, correlation with fruit weight per plant in low light and adequate light are the best indicators for selecting genotypes tolerant to low light. Based on these indices, genotypes “9318,” “9314,” “321,” “324,” and “523” had the highest ranks and more tolerance to low light, and might be successfully cultivated in low light areas.

Evaluation of Drought Stress Tolerance in Some Faba Bean Genotypes Using Drought Tolerance Indices

To evaluate drought tolerance in faba bean genotypes, 21 genotypes were studied in a randomized complete block design with three replications under normal irrigation and drought stress conditions. The experiment was conducted in 2017-2018 at research station of Gorgan, Iran. Indices such as stress tolerance index (STI), stress susceptibility index (SSI), tolerance (TOL), mean productivity (MP), geometric mean productivity (GMP), yield index (YI) and yield sustainability index (YSI) were calculated for all genotypes according to grain yield in normal irrigation and stress conditions. Based on analysis of variance results, there was a significant difference among the genotypes in terms of grain yield in both environments (normal irrigation and drought stress). The results of correlation showed that STI, MP, GMP and TOL are suitable for selection of high-yielding genotypes in both environments, among which STI and MP were the most suitable indices to select drought-tolerant genotypes. Based on STI, MP and GMP indices, GF-65 genotype was classified drought-tolerant, and GF-525 and GF-21 were susceptible according to TOL and SSI indices. Results of cluster analysis showed that GF-66, GF-62, GF-75 and GF-67 were superior compared to other genotypes based on YSI, YI, GMP, MP and STI indices, and utilization of these genotypes may be recommended to achieve high yields in drought stress conditions.

Screening of Wheat Genotypes for Nitrogen Deficiency Tolerance Using Stress Screening Indices

An increased awareness of environmental protection and sustainable production raise the necessity of incorporating the selection of low nitrogen-tolerant winter wheat cultivars for high yield and quality in the breeding process. This selection can be assisted by using stress screening indices. Our study aimed to evaluate and compare a number of stress screening indices and to determine and select the most nitrogen deficiency-tolerant winter wheat cultivars for further breeding. The experiment included forty-eight winter wheat cultivars from eight different countries that were grown for two consecutive years at three different locations under low-nitrogen (LN) and high-nitrogen (HN) conditions. The results emphasized the importance of applying the appropriate stress screening indices in evaluating and selecting nitrogen deficiency-tolerant wheat cultivars. The promising stress screening indices were the mean productivity index (MP), geometric mean productivity index (GMP), harmonic mean index (HM), stress tolerance index (STI) and yield index (YI). They identified cultivars Sofru, BC Opsesija and MV-Nemere as the most tolerant cultivars to LN conditions for grain yield. The same indices classified U-1, OS-Olimpija, Forcali, Viktoria and BC Tena cultivars as the most tolerant to LN conditions for the grain protein content. Using the tolerance index (TOL), yield stability index (YSI) and relative stress index (RSI), the Katarina and Ficko cultivars were denoted as LN-tolerant cultivars in terms of the grain yield and Isengrain, Tosunbey, Vulkan and BC Darija in terms of the grain protein content.

Selection approaches to the variation of responses to soil compaction stress among maize hybrids (Zeamays L.)

AbstractSoil compaction stress can strongly affect plant growth, development and productivity. Effects of different levels of soil compaction were investigated in 18 maize hybrids during field and greenhouse experiments. Maize hybrids in the field experiments were subjected to low (L) or high (H) and in the greenhouse experiments to low (L: 1.10) and high (C: 1.60 g cm−3 soil) soil compaction level. Differences between maize hybrids grown under non‐stress and stress conditions were found in a decrease in grain yield (GY), grain number (GN), weight of 1,000 grain (W‐1000), seedling dry matter (DM), emergence (EM), plant height (H), leaf area (LA) and leaf greening (SPAD). Stress susceptibility index (SSI), geometric mean productivity index (GMP) and tolerance index (TI) were evaluated by determining the effects of low (L) or high (H) soil compaction levels on grain yield (GY) or dry matter of the above‐ground part (DM). The values of SSI, GMP and TI enabled us to rank the tested hybrids with respect to their susceptibility to soil compaction stress. SSI and TI made it possible to identify maize hybrids resistant and sensitive to soil compaction stress. Changes in growth traits were greater in the hybrids with high SSI and TI. Correlation coefficient (r) between stress susceptibility index (SSI) of maize hybrids in the field and greenhouse experiment was high and statistically significant. This observation may indicate that genetically determined susceptibility to soil compaction stress in maize hybrids was similar throughout ontogenesis.

Drought Tolerance Screening for Rice Genotypes Using Various Drought Indices in Lamjung, Nepal

A field experiment was conducted during rainy reason of 2018 to rectify stable and high yielding rice varieties at moisture stress condition at Lamjung, Nepal. 13 rice genotypes were evaluated at randomized complete block design (RCBD) with three replications. About 5 cm stagnant water was maintain in irrigated field until one month before harvesting whereas in rainfed field no extra irrigation was provided and drainage of excess rainfall water. Drought indices such as tolerance index (TOL), stress susceptibility index (SSI), yield stability index (YSI), Stress tolerance index (STI), mean productivity index (MP), geometric mean productivity index (GM) were computed. Results showed significantly different for all drought indices Average yield reduction was 27% . Ys was positive and significant association with Yp. The MP, GM and STI were positive correlation with grain yield under both environments whereas SSI and YSI was negative non-significant association with both stress and normal condition yield. In principle component analysis (PCA) two component explained more than 99% variation. Combined analysis showed that Radha 11, Radha 13, DRR 44, NR 119, Sukhadhan 5 and Ghaiya 2 were top performer in stress condition whereas NR 119 reported the lowest yield reduction in stress condition. Sawa Mansuli Sub-1 most susceptible under stress condition exhibiting 54 % yield reduction in stress condition. Manabahu was stable but lower yielding varieties.

Assessment of Azerbaijan Durum Wheat Genotypes Under Drought and Non-Stress Conditions

In this study, as a genetic materials 50 wheat genotypes from National Genebank of Genetic Resources Institute of ANAS were tested in a randomized complete block design in two replications under drought and normal conditions in Gobustan and Absheron regions, Azerbaijan Republic during 2016-2017 growing season. Analysis of variance indicated that there were highly significant differences among the genotypes with regard to all the traits under two experimental condition. The correlation coefficients showed that stress tolerance index (STI), mean productivity (MP), harmonic mean (HM) and geometric mean productivity index (GMP) were the most desirable selection criteria for high yielding and drought tolerant genotypes. Principal component analysis and biplot showed that genotypes № 15, 28, 4, 13 and 6 were more stable under irrigated and rain-fed conditions. These genotypes can be recommended to be used as donor parents for drought tolerance genes in wheat breeding programs for drought-affected areas of Azerbaijan Republic.

Different statistical procedures for selection of salt tolerant barley genotypes at germination stage

Growing of salt tolerant crops is a good option to obtain economical yields from saline areas and screening salt tolerant plants, particularly in early growth stages as one of the most important determinants of high yield, is important. So a laboratory experiment was performed to assess several indices for identifying barley genotypes with better performance under saline conditions. The effect of salinity stress was studied through an analysis of the dry matter production, that yielding results showed significant differences among genotypes. The multiple statistical procedures which have been used in this study showed that mean productivity and geometric mean productivity indices could be a useful indicator of desirable genotypes in both stress and non-stress conditions at this stage especially in high level of salinity. The majority of used tolerance indices indicated that MBS8715 was the best barley genotype showing the highest stress resistance for the most salt concentration.

Spectral assessment of drought tolerance indices and grain yield in advanced spring wheat lines grown under full and limited water irrigation

Because wheat varieties exhibit a high genotype×environment interaction, several drought tolerance indices (DTIs) have been developed to assist breeders in selecting genotypes with good performance under contrasting water conditions. We compared the relative yield of advanced breeding wheat lines under both well-watered and limited water irrigation conditions using different DTIs and evaluated how spectral reflectance indices (SRIs), as rapid and non-destructive tools, can effectively monitor DTIs and grain yield. Sixty-five recombinant inbred lines (RILs) developed from a cross between drought-tolerant (Sakha 93) and drought-sensitive (Sakha 61) genotypes were subjected to full irrigation (FI) and limited water irrigation (LWI) in the 2014 (F6), 2015 (F7), and 2016 (F8) growing seasons. Eight vegetation- and water-SRIs calculated from canopy reflectance under FI and LWI, and taken at the heading and middle grain filling stages, were related to the DTIs and grain yield. We found that the yield performance of the RILs was not consistent across the two water regimes. Selection based on the DTIs, the stress susceptibility index and the tolerance index failed to identify RILs that had very low yields under both treatments. However, the mean productivity index (MPI) and the geometric mean productivity index (GMP) enabled us to identify RILs that produced desirable yields under both full and limited irrigation, and these drought tolerance indices further exhibited a high heritability. Across the three years of investigation and at the heading and middle grain filling stages, these DTIs were best described either by the vegetation-based dry matter content index (DMCI) or the water-based normalized multi-band drought index (NDMI), or a combination of both. In conclusion, our results demonstrate that a combination of near infrared (NIR) and shortwave infrared (SWIR)-based SRIs can be used as a fast and low-cost predictor for selecting wheat genotypes with superior yield under different water regimes.

Evaluating the best indicators and identifying the most tolerant varieties to draught in potato varieties

In order to evaluate the drought tolerance indicators in six potato varieties of Agria, Asterix, Serenad, Draga, Diamant and Cosima and determine the best indicators and identifying the most tolerant varieties using performance measurement in normal irrigation and drought stress conditions, Two separate experiments at two irrigation regimes in a split plot design (split-plot) based on a randomized complete block were performed in Three replications in Ardabil Agricultural Research Station located in Alaroq village (12 km south of Ardabil). Six drought tolerance indices were calculated for tuber yield varieties. Geometric mean productivity index, mean productivity and stress tolerance index were highly correlated significantly with performance in both environments and were introduced as suitable indicators of identifying the probable varieties to water shortage in potato. Principal components analysis showed that 95% of the total variation is justified with the first component (tuber yield by 62%) and second component (with a tolerance of 33%). Agria and Serenad were presented d as appropriate figures in this study with high yield potential and tolerance to water deficit conditions in the experimental conditions of this study.

English

The main purpose of this study was to evaluate the effect of drought stress on seed yield of some winter rapeseed cultivars and to study relevant drought tolerance indices, along with identifying resistant cultivars to drought stress. Plant materials were sown in split plot arrangement based on a randomized complete blocks design, at Islamic Azad University of Tabriz research field. Three drought stress levels which include 80, 130, and 180 mm water evaporation from class A pan were considered as the main factor levels, while seven winter rapeseed cultivars which include Licord, Okapi, Opera, S.L.M.046, Zarfam, Modena, and Talaye were arranged to sub plots. Studied quantitative drought tolerance indices were, tolerance index (TOL), mean productivity (MP), stress susceptibility index (SSI), stress tolerance index (STI), geometric mean productivity (GMP), yield index (YI), yield stability index (YSI), and percentage of yield reduction (%Reduction). The yield stability analysis of the studied cultivars was done by GGE biplot method. According to the results derived from principal component analysis and regarding evaluation of correlation coefficients among indices, STI and GMP were selected as the two superior indices for identifying drought resistant cultivars. Three dimensional scatter plots based on STI and GMP indices showed that Licord and Talaye were the most suitable cultivars, and were situated in group, A. In addition, Modena and Zarfam were identified as sensitive and resistant to drought stress, respectively.

English

In order to evaluate drought tolerance indices of lentil cultivars in the Ardabil region, a factorial experiment based on randomized complete block design with three replications was arranged at the Agricultural Research Station of Islamic Azad University, Ardabil branch, Ardabil, Iran, in 2010. The factors included two conditions of planting levels (irrigation and non-irrigation) and five lentil cultivars (ILL 1180, ILL 1324, ILL 1251, ILL1237, and native cultivars). Irrigation included complete irrigation from planting until maturity and non-irrigation from seed emergence until harvesting.  The results showed that the length of vegetative and reproductive periods, total number of pod and seed per plant, 100-seed weight, seed yield and harvest index were of higher rates under irrigation than the stress (non-irrigation). Also, it was found that ILL 1180 and ILL 1324 cultivars possessed the highest and lowest values for all traits, respectively. Yield loss of the ILL 1180 under stress, was about 308.22 kg/ha (23.31%) than the normal conditions. This value for the ILL 1324 was approximately 448.53 kg/ha (35.51%). Also, ILL 1180 showed the lowest tolerance against stress (TOL) and stress susceptibility index (SSI) and the highest mean productivity (MP), geometric mean productivity (GMP) and stress tolerance index (STI) indices. ILL 1324 possessed the highest TOL, SSI and STI and ILL1237 showed the lowest MP and GMP indices. So, ILL1180 and ILL1251 were the superior cultivars under both conditions in terms of high yield and tolerance against drought stress. ILL1237 was distinguished as the most susceptible cultivar as well.   Key words: Lentil, yield, normal and stress conditions, drought tolerance index.

Assessing Genetic Diversity of Rice Varieties under Drought Stress Conditions

In order to compare different rice genotypes grown under drought stress conditions a field experiment was conducted. In this study thirty different genotypes of native, breeded and upland cultivars were evaluated. Analysis of variance showed significant differences among genotypes in respect of all vegetative and morphological traits. Genotypes were devided into three groups by cluster analysis based on all studied traits with minimum variance method (Wards Method). The total average indicates significant differences among groups in respect of all morphological and physiological characteristics. In addition, eight drought stress tolerance indices including: sensitivity to stress index (SSI), drought response index (DRI), relative drought index (RDI), tolerance index (TOL), mean productivity index (MP), stress tolerance index (STI), geometric mean productivity index (GMP) and harmonic mean index (HM) were calculated according to their grain yield under drought stress and normal conditions. In general, results of this experimnet revealed that, among rice cultivars Domsephid, Deylamany, Hasansaraei, Sadri, Anbarboo and Domsiah had the highest sensitivity referring to drought stress and produced the lowest grain yield. Also, genotypes of IR24 (breeded of IRRI), Nemat, Sephidroud, Kadoos and Bejar (breeded of Iran) and Vandana, upland cultivar (originally from India) had the highest tolerance to drought stress and produced the highest grain yield. In conclusion, it was suggested that, these cultivars are suitable for drought stress conditions and are appropriate for hybridization with the aim of increasing drought tolerance.