Terminal Stress Conditions Research Articles

Performance of pearl millet genotypes under drought and terminal stress condition for their suitability under arid and semi arid regions

The field experiment was conducted at ICAR-AICRP on Pearl Millet Farm, Mandor, Jodhpur during summer season of 2015-16 in Randomized Block Design (RBD) with three replications. Twenty two genotypes were evaluated under normal as well as terminal stress condition. The suitability of genotypes was identified on the basis of physiological parameters like drought tolerance index (DSI), drought tolerance efficiency (DTE), grain reduction percentage (GRP), threshing percentage (TP) and harvest index (HI) in addition to 50% flowering, productive tillers, grain yield, stove yield, days to maturity. Among different genotypes, J-2510, MIR-1252, 06555B, J-2551 and MIR 1252 produced comparatively higher grain yield under both the conditions. The lowest drought resistance index (DSI) was observed in MIR 1252, 6555B and J-2510 which indicated their better suitability under terminal stress and heat stress conditions.

Screening of Pearl Millet Genotypes for High Temperature and Drought Tolerance Based on Morpho-Physiological Characters

Aims: Screening of pearl millet genotypes lines for high temperature and drought tolerance.
 Study Design: Randomized Block Design (RBD) with three replications.
 Place and Duration of Study: ICAR-AICRP on Pearl Millet, Mandor during summer 2017-18.
 Methodology: Fifteen genotypes (J-2290, J-2340, J-2479, J-2500, J-2503, J-2507, J-2517, J-2534, JMSB-9904, JMSB-101, JMSB-20064, JMSB-20102, JMSB-20071, JMSB-20082 and JMSB-20091) of pearl millet received from Main Pearl millet Research Station, Junagadh Agricultural University, Jamnagar were evaluated during summer season of 2017-18 at research Farm of ACIRP on pearl millet, Mandor, Agricultural University, Jodhpur under terminal moisture stress and irrigated conditions in two sets of randomized block design with three replications. Grain yield, stover yield, Relative Water Content (RWC), harvest index, threshing percentage and chlorophyll content were recorded.
 Results: The suitability of the genotypes was judged in terms of grain yield, stover yield, RWC, harvest index, threshing percentage and chlorophyll content. The results showed that due to the terminal stress, the mean performance of all yield attributing characters including grain yield and chlorophyll, RWC and seed setting was reduced. The inbreds J-2479, J-2503 and J-2507 were high yielders due to high seed setting percentage under terminal stress conditions.
 Conclusion: The lines viz., J-2479, J-2503 and J-2507 can be used for further breeding programme to develop varieties suitable under high temperature and low moisture conditions.

Rootstock Genotypes Shape the Response of cv. Pinot gris to Water Deficit

Understanding the physiological basis underlying the water stress responses in grapevine is becoming increasingly topical owing to the challenges that climate change will impose to grapevine agriculture. Here we used cv. Pinot gris (clone H1), grafted on a series of tolerant (1103Paulsen; P), sensitive (SO4) and recently selected (Georgikon28; G28, Georgikon121; G121, Zamor17; Z17) rootstocks. Plants were either subjected to reduced water availability (WS) or maintained at pot capacity (WW). Photosynthetic (light response curves), stomatal and in vivo gas exchange analysis were carried out as well as dynamics of daily water use (WU), leaf area accumulation with affordable RGB imaging pipelines and leaf water potential. Significant genotypic variation was recorded between rootstocks for most of the traits analyzed under optimal conditions with P and SO4 showing a more vigorous growth, higher CO2 assimilation rate, stomatal conductance and stomatal density per unit of leaf area than G28, G121, Z17 (p < 0.001). Under WS, rootstocks induced different water stress response in Pinot gris, with G28 and G121 showing a higher sensitivity of water use to reduced water availability (WS) (p = 0.021) and no variation for midday leaf water potential until severe WS. P, Z17 and to some extent SO4 induced a pronounced near-anisohydric response with a general WU maintenance followed by reduction in leaf water potential even at high levels of soil water content. In addition, G28 and G121 showed a less marked slope in the linear relationship between daily water use and VPD (p = 0.008) suggesting elevated sensitivity of transpiration to evaporative demand. This led to an insensitivity for total dry weight biomass of G28 and G121 under WS conditions (p < 0.001). This work provides: (i) an in-depth analysis for a series of preferable traits under WS in Pinot gris; (ii) a characterization of Pinot gris × rootstock interaction and a series of desirable traits under WS induced by several rootstocks; (iii) the potential benefit for the use a series of affordable methods (e.g., RGB imaging) to easily detect dynamic changes in biomass in grapevine and quickly phenotype genotypes with superior responses under WS. In conclusion, the near-isohydric and conservative behavior observed for G28 and G121 coupled with their low vigor suggest them as potential Pinot gris rootstock candidates for sustaining grapevine productivity in shallow soils likely to develop terminal stress conditions.

Breeding implications of drought stress under future climate for upland rice in Brazil.

Rice is the most important food crop in the developing world. For rice production systems to address the challenges of increasing demand and climate change, potential and on-farm yield increases must be increased. Breeding is one of the main strategies toward such aim. Here, we hypothesize that climatic and atmospheric changes for the upland rice growing period in central Brazil are likely to alter environment groupings and drought stress patterns by 2050, leading to changing breeding targets during the 21st century. As a result of changes in drought stress frequency and intensity, we found reductions in productivity in the range of 200-600kg/ha (up to 20%) and reductions in yield stability throughout virtually the entire upland rice growing area (except for the southeast). In the face of these changes, our crop simulation analysis suggests that the current strategy of the breeding program, which aims at achieving wide adaptation, should be adjusted. Based on the results for current and future climates, a weighted selection strategy for the three environmental groups that characterize the region is suggested. For the highly favorable environment (HFE, 36%-41% growing area, depending on RCP), selection should be done under both stress-free and terminal stress conditions; for the favorable environment (FE, 27%-40%), selection should aim at testing under reproductive and terminal stress, and for the least favorable environment (LFE, 23%-27%), selection should be conducted for response to reproductive stress only and for the joint occurrence of reproductive and terminal stress. Even though there are differences in timing, it is noteworthy that stress levels are similar across environments, with 40%-60% of crop water demand unsatisfied. Efficient crop improvement targeted toward adaptive traits for drought tolerance will enhance upland rice crop system resilience under climate change.

Effect of Terminal Drought Stress on Morpho-physiological Traits of Wheat Genotypes

Development of wheat varieties with low moisture requirements and their ability to withstandmoisture stress may cope-up well with the on-coming peril of drought conditions. Ten wheat genotypesincluding two new strains, PBGST-3, Hero, Bhittai, Marvi, Inqlab, Sarsabz, Abadgar, Kiran, Khirman andPBGST-4 were sown in split plot design with factorial arrangement in four replications at ExperimentalField, Department of Plant Breeding & Genetics, Sindh Agricutlure University, Pakistan during 2012-13.The results revealed that water stress caused significant reductions in all morpho-physiological traits. Thegenotypes differed significantly for all the yield and physiological traits. The interaction of treatments ×genotypes were also significant for all the traits except plant height, productive tillers/plant, grains/spikeand harvest index, were non-significant which indicated that cultivars responded variably over the stress treatments suggesting that breeders can select the promising genotypes for both stress and non-stressenvironments. Among the genotypes evaluated Bhittai, Kiran-95, PBGST-3 and Sarsabz showed goodperformance as minimum reductions occurred under terminal stress conditions for all the traits studied.Hence, above mentioned genotypes were considered as drought tolerant group. The high positive correlationsof physiological traits like chlorophyll content and relative water content with almost all yield traits indicatedthat these physiological traits could serve as reliable criteria for breeding drought tolerance in wheat. Thenegative correlations of electrolyte leakage with several important yield traits indicated that though thisphysiological trait has adverse effect on yield attributes, yet it could reliably be used to distinguish betweendrought tolerant and susceptible wheat genotypes.

Effect of Terminal Water Stress and Benzyl Adenine on Osmoregulants in Pearl Millet [Pennisetum glaucum(L.) R. Br.] Genotypes

The effect of benzyl adenine (BA) soaked seed treatment and terminal water stress in leaf tissues of four genotypes of pearl millet (J-2340, 95444B, J-2290 and JMS-101B) under field conditions was studied during summer season. The leaves were collected at terminal water stress stage and used for proline, free amino acids, soluble sugars and phenol estimation. Imposition of terminal stress increased all these four parameters. Free amino acids (FAA) were accumulated in all the genotypes on imposing terminal stress condition. The overall mean for FAA content was higher in drought sensitive genotypes J-2290 and JMS-101B as compared to tolerant genotypes. Water soaked seed treatment showed higher free amino acids. Terminal stress condition increased proline content (2.2 fold) than the irrigated condition and it was accumulated in all the genotypes with higher accumulation in J-2340 and J-2290. Among the presoaking treatments, less proline accumulation was observed in water soaked and BA soaked treatments. On exposure to the terminal stress, all the genotypes showed rise in the total soluble sugars and the greater accumulation was observed in genotype JMS-101B, while the least was in the genotype 95444 B. The overall mean of total soluble sugars was significantly higher in the genotype JMS-101B and the lowest in the J-2340. The presoaking treatments did not show any significant effect. The phenol content was also increased under the terminal stress condition in all the genotypes and a significant higher accumulation was in the genotype J-2290. The overall mean values of phenol in genotypes were the highest in JMS-101B and minimum in the genotype 95444B. The presoaking treatments viewed the highest content in the BA soaked treatment and the lowest in the control.

Proline, Glycine, Betaine and Dry Matter Accumulation in Rabi Sorghum Under Moisture Stress

In order to evaluate physiological traits related to biochemical basis of drought tolerance under moisture stress, a field experiment with ten sorghum genotypes was carried out in split plot design with three replications. Seeds were grown separately under three moisture regimes viz; moisture stress condition with irrigation applied at the time of sowing, terminal stress condition with irrigation applied at the time of sowing and panicle initiation stage and non stress condition with irrigation applied at various critical growth stages. The accumulation of proline and glycine betaine was higher under moisture stress than terminal stress and non-stress condition. Accumulation of proline and glycine betaine content was recorded at the time of 50% flowering and at dough stage to estimate the efficiency of drought tolerance. Among the genotypes under study, RSV 1237 accumulated more leaf proline, whereas, RSV 1572 accumulated more glycine betaine at 50% flowering stage and dough stage under moisture stress. Genotypes differed significantly with respect to leaf, stem, panicle and total dry matter per plant. RSV 1237 and RSV 1572 had better partitioning of dry matter into reproductive parts under moisture and terminal stress conditions. It was concluded that these genotypes could be useful in sorghum breeding for drought tolerance.

Tolerance of 42 Bread Wheat Genotypes to Drought Stress after Anthesis

The present research characterized yield and yield components of 42 wheat genotypes after terminal drought stress. The experiment was in twice replicated simple rectangular lattice design, conducted at irrigated and terminal stress conditions during 2006-2007. These study genotypes had significant differences for grain yield at level of 1%. Genotypes 4057, Viking/5/Gds/4.., Sabalan and 5041 respectively with 6.313, 6.159, 5.793 and 5.774 t ha(-1) had the highest yield and Gascogen has the lowest yield with 2.561 t ha(-1). Mean of total grain yield for under study genotypes was 5.628 t ha(-1) in non-stress and 3.305 t ha(-1) in drought stress conditions. Drought stress decreased amount of grain yield 2.323 t ha(-1) that was noticeable. Interaction of Genotype x environmental conditions was significant at probability level of 1% for grain yield. Yield of all genotypes in drought condition was lower than non-stress condition. Genotypes Viking/5/Gds/4/Anza/3/Pi.., Sabalan, 4061,4057 and 4041 had more yield in non-stress condition and MV17/Zrn, Sabalan, Saysonz and 4032 in stress condition. Stress intensity pay attention to total grain yield was 42%. Genotypes Viking/5/Gds/4/.. and Sabalan had high grain yield and was better than other genotypes and controls (Toos and Crosse Shahi), according to GMP, STI and MSTI. And had the most amount of stress tolerance index as compared with other genotypes confirms this subject. Correlation of yield with other traits was not significant in non-stress condition. In drought condition, correlation of grain yield with 1000 grain weight and total number of tillers per plant was positively significant. ANOVA showed significant differences between osmotic pressures for coleoptile length, between genotypes for mean and maximum coleoptile length and between interactions of genotypes x osmotic pressures for mean and maximum coleoptile length. Mean comparisons showed the highest total, mean and maximum coleoptile length in -7 bar PEG+I ml L(-1) potassium humate treatments. Genotypes Sardari and Sabalan had the highest amounts of total, mean and maximum coleoptile length. With due attention to interaction genotype x osmotic pressures, genotypes Sardari, Sabalan and 4057 in -7 bar PEG+1 ml L(-1) potassium humate had the most amounts of noted characters than others. In conditions of this experiment, potassium humate caused increase in tolerance rate of genotypes against drought stress.