Leaf Firing Research Articles

Genetic Evaluation of Heterosis and Combining Ability of Quality Protein Maize (Zea mays L.) Hybrids under Terminal Heat Stress Conditions

Background: The development of quality protein maize (QPM) hybrids tolerant to terminal stress environments has been an essential strategy for reducing the associated loss in grain yield. A study by Badu-Apraku et al., (2019) employed line × tester analysis in QPM breeding, highlighting its efficacy in selecting QPM hybrids. While QPM varieties resistant to disease, drought and environmental stresses have been developed conventionally, the adoption of improved QPM genotypes in farmers’ field is restricted mainly due to lack of proper team effort among maize breeders, farmers, agricultural extension workers and other relevant stakeholders. Methods: In line × tester mating design, six lines and three testers were crossed under heat stress environment and 18 F1s along with parental lines were evaluated along with check varietal during summer season, 2023, P.G research farm, CUTM, Paralakhemudi, Odisha. The objective of the current study was to evaluate parental lines and its crosses based on combining ability and heterosis. Result: ANOVA revealed significant to revealed significant differences for all the traits between parents, lines, testers and lines vs testers, except for cob height, chlorophyll content and canopy temperature. 𝛔2GCA/𝛔2SCA values for parents/hybrids recorded lower than unity for all the trait studied suggesting preponderance of non-additive gene action. Parental lines CML149, CML143 and CML330 are the best general combiners for early flowering, grain yield per plant and antioxidant status. Among eighteen crosses, two hybrids CML149 × CML330 and CML143 × CML193 recorded significant SCA effects for early flowering, grain yield per plant and antioxidant levels. Hybrids CML149 × CML330 (33.31%) and CML143 × CML193 (28.31%) noted significant standard heterosis for grain yield per plant over commercial check, HQPM-1. Hybrids CML149 × CML330 and CML143 × CML193 were resilient to terminal heat stress as they didn’t exhibit signs of leaf firing, tassel blast, root lodging and loss of yield.

Effect of Salinity on Warm Season Turf Grass Species

The demand for salinity tolerant turf grasses is increasing due to augmented use of effluent or low-quality water for turf irrigation. Fresh water, along with soil Stalinization in many locations, has raised the requirement for salt-tolerant turf grass screening. Physiological responses to salinity and relative salt tolerance of Five C4 turf grasses, two variety ofCynodon dactylon(Bermuda grass), Zoysia matrella (Manilla grass), Zoysia japonica(Zoysia Grass) and Paspalum notatum(Bahia grass) were investigated during the study at Department of Horticulture Sam Higginbottom University of Agriculture Technology and Science, Prayagraj. Turf grasses were planted in plastic pots filled with sand: cocopeat: vermiculite (2:1:1) and irrigated with different concentration of salinity levels (0.6, 5.0, 10.0, 15 dS m-1). Salinity tolerance was evaluated based on leaf length leaf Wirth leaf firing, shoots and root growth reduction, proline content, total chlorophyll content RGB content and relative water content was subjected to analysis of variance. Among the four turf grass species Bahia grass found to be most salt tolerant turf grass followed by Z. matrella while Zosia japonica was least tolerant turf grass against salt stress.

Advanced Turf-type Bermudagrass Experimental Genotypes Show Marked Variation in Drought Response

Bermudagrass (Cynodon sp.) is one of the most commonly used warm-season turfgrasses in the southern areas and transition zone of the United States. Due to the increasing demand for water resources and periodic drought, it is important to improve the drought resistance of bermudagrass for water savings and persistence under drought stress. This study was conducted to determine whether experimental bermudagrass genotypes have improved drought resistance compared with the standard cultivars Tifway and Riley’s Super Sport (Celebration®) at Stillwater, OK. The trials were designed as randomized complete blocks with four replications in Expt. I and three replications in Expt. II. In each experiment, genotypes were subjected to progressive acute drought conditions using polyethylene waterproof tarps to exclude precipitation over a period of at least 72 d. Bermudagrass entries were evaluated for turfgrass quality, leaf firing, normalized difference vegetation index, and live green cover at least once each week during the dry-down. Substantial drought response variations were found in this study, and all parameters were positively and highly correlated. A turf performance index (TPI) was assembled based on the number of times an entry ranked in the top statistical group across all testing parameters on each date. ‘DT-1’ (TifTuf®) and OSU1221 had the top TPI in both experiments. Most of bermudagrass experimental genotypes had equal or greater TPI than the standard Tifway, showing improved drought resistance through breeding effects. The identification of superior drought resistance experimental genotypes provided useful information to breeders on cultivar release.

Effect of antecedent drought stress on spring green‐up in turf‐type bermudagrasses

AbstractWinterkill is a major concern for turf‐type bermudagrasses [Cynodon dactylon (L.) Pers. and C. dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] when cultivated in the US transition zone and frequently occurring drought conditions challenge bermudagrass management. Therefore, developing new bermudagrasses with both drought resistance and winter survivability are needed for the future sustainability of the turfgrass industry in the transition zone. How these two traits interact within bermudagrass populations is not widely reported. Accordingly, the objectives of this study were to estimate reliability for spring green‐up (SG) (as an indicator of winter survivability) and drought response in turf‐type bermudagrasses. A total of 77 experimental genotypes and 7 cultivars were planted in a randomized complete block design with 3 replications over 2 years in Goodwell, OK, USA. Substantial genetic variations were found for drought response and SG parameters when analyzed by year, but variations for SG parameters and leaf firing were not significant when analyzed across years. The reliability estimates for drought response ranged from low to moderate (i2 = 0.24–0.61), whereas the subsequent estimates for SG were low (i2 = 0.13–0.33), suggesting poor reliability. The low‐to‐moderate reliability values in SG were likely due to antecedent drought injuries, indicating that winter survivability and drought resistance may need to be evaluated in separate trials.

Genetic variability and QTL mapping of winter survivability and leaf firing in African bermudagrass

AbstractTurf‐type bermudagrass is susceptible to winterkill when grown in transition zone climates. Minimizing water use in turfgrass management is of societal significance. African bermudagrass (Cynodon transvaalensis Burtt‐Davy) has been extensively used to cross with common bermudagrass (C. dactylon Pers. var. dactylon) in the creation of F1 hybrid cultivars. Little information regarding the molecular basis of winter survivability and drought resistance in African bermudagrass is available. Accordingly, the objectives of this study were to quantify genetic variability and identify quantitative trait loci (QTL) associated with winter survivability traits (spring greenup, SG; spring greenup percent green cover, SGPGC; winterkill, WK), and leaf firing (LF) in African bermudagrass. A total of 109 first‐generation self‐pollinated (S1) progeny of ‘OKC1163’ were evaluated in a field trial in a randomized complete block design with three replications for four seasons. Significant genetic variation existed for all the traits examined, and the broad‐sense heritability estimates ranged from .36 to .54 for the winter survivability traits and .80 for LF. Ten QTL were identified for winter survivability traits and two for LF based on a preexisting high‐density linkage map, which was aligned, reoriented, and renamed as to a recently published reference genome. Seven of 12 QTL were consistently identified at least in 2 yr. The colocation of two QTL, one for winter survivability and another for LF, suggests the possibility of improving both traits together. Findings provide new insights to genetic control of winter survivability traits and LF and contribute genetic resources for marker‐assisted selection in turf‐type bermudagrass improvement.

Combining Ability and Heterosis of QPM Hybrids for Yield, Qualitative and Quantitative Traits under Heat stress in Different Environments

With increasing climate change relates to rise in mercury causing heat stress in maize. Heat stress tolerance has appeared to be one of the foremost trait to overcome this situation. Relative magnitude of variances depicted additive and non-additive gene action for the expression of these characters were more extrusive for all the traits studied. GCA and SCA both showed huge collaboration with climate for all the characteristics. Parents NBPGR-36548 (P4), VL-153237 (P5) and BHU QPM-2 (P2) were found to be good general combiners for grain yield per plant, chlorophyll content, oil content and starch content. Indicating that they could be good parental lines in hybridization programs. The scope of heterosis communicated by various crosses was from 0.71 % (P2 X P6) to 45.11% (P5 X P6) in E1, from 0.42% (P1 X P7) to 5.69% (P1 X P8) in E2 and 18.92% (P4 X P8) in E3. The better performing five crosses P5 X P7, P5 X P6, P4 X P8, P5 X P9 and P4 X P5. Crosses between good x average, average x average and good x good shows greater economic heterosis and exhibited high SCA effects for yield under HS. These best Hybrids showed no side effects of leaf firing, tassel blast, root lodging and no severe loss of yield in the present investigation. These crosses additionally should be assessed further multi location in enormous scope.

Drought response of 10 bermudagrass genotypes under field and controlled environment conditions

AbstractFresh water scarcity is increasingly affecting urban landscapes, and the best strategy for sustaining the turfgrass industry would be to create, select, and use drought‐resistant genotypes. Bermudagrasses (Cynodon spp.) have different mechanisms to survive drought stress either by growing long roots, stomatal regulation, or accumulating biochemical solutes in the leaf. The drought response of 10 bermudagrasses was evaluated under two environments: (a) unrestricted root zone in the field and (b) restricted 17‐cm root zone in a greenhouse. Each study consisted of four commercially available (‘Latitude 36’, ‘Tifway’, ‘TifTuf’, and ‘Celebration’) and six experimental genotypes (OSU1337, OSU1403, OSU1439, TifB16101, TifB16113, and TifB16120). In the field study, all the genotypes survived the 60‐ and 49‐d dry‐down periods in 2017 and 2018, respectively, without completely browning off. Results showed a range of drought performance among genotypes, with TifTuf and Latitude 36 being the best‐ and worst‐performing industry standards, respectively. TifB16101, TifB16120, and TifB16113 were consistently the top performers with a leaf firing (LF) and turf quality (TQ) above 6, lower canopy temperature (CT), and greater normalized difference vegetation index (NDVI) values in the field. However, when grown in 17‐cm pots, TifTuf, TifB16113, and TifB16120 demonstrated a TQ below 6 within 6 and 9 days of drought (DOD) in 2019 and 2020, respectively. The discrepancy between studies suggests that these genotypes may have the ability to extract water from deeper soil profiles when root zones are unrestricted. Furthermore, these findings reinforce the importance of soil depth in maintaining turfgrasses without supplemental irrigation.

Effect of salicylic acid and progesterone on physiological characteristics of Kentucky bluegrass under salinity stress

Salinity is one of the most important limiting factors in plant growth. It is also a predominant constraint that impairs grass growth and quality. Plant hormones play important roles in the capability of plants to adapt to environmental stresses. Hence, the impact of two plant growth regulators (PGRs) i.e. salicylic acid (SA) and progesterone (P4) was studied on biological characteristics of Poa pratensis in saline conditions in a greenhouse experimnt. The experimental treatments were composed of salinity at four levels (0, 2, 4, and 6 dS m-1) and six levels of PGRs (control, 1 mg L-1 P4,10 mg L-1 P4, 1 mM SA, 3 mM SA, and 1 mg L-1 P4 + 1 mM SA). The results showed that leaf firing percentage was increased with the excess in salinity, but the use of SA and P4 eased the effects of salinity stress and reduced leaf firing under salinity. 6 dS m-1 and 3 mM SA salinity caused to the maximum electrolyte leakage. The highest relative water content was observed in 4 dS m-1 salinity and 1 mM SA treatment. The highest glycine betaine was related to 6 dS m-1 NaCl and no hormone application. Salinity increased total protein and catalase, and the simultaneous use of P4 and SA exhibited the highest total protein and catalase content, whilst the control plants showed the lowest ones. The application of salinity stress reduced chlorophyll content, but SA and P4 increased it. The application of the two growth regulators improved carotenoid content under salinity stress. Overall, the results showed that the application of SA and P4 improved salinity tolerance and increased pigments and antioxidant enzyme activities.

The Spectral Reflectance Response of ‘Riviera’ Common Bermudagrass to Increasing Saline Irrigation Concentrations

The availability of freshwater is a growing concern throughout the world as it is an increasingly valuable and limited resource. Alternative water resources such as recycled water low in quality and high in salinity are now frequently used to irrigate turfgrass. However, irrigating with highly saline water can affect the growth, performance, appearance, and quality of turfgrass. Bermudagrass (Cynodon sp.) is the most commonly used turfgrass throughout the southern United States. In this study, the spectral reflectance and visual response of ‘Riviera’ common bermudagrass (Cynodon dactylon) were evaluated by consecutively irrigating with 12 salinity concentrations (4–48 dS·m−1) in increments of 4 dS·m−1 via manual overhead irrigation for 30 days. The experiment was replicated in time in a controlled environment with four replications for each salinity treatment and control. ‘Riviera’ maintained a leaf firing (LF) value above 5 (rated on a scale from 1 to 9) when irrigated with 28 dS·m−1 for 30 days. Also, the LF value did not fall below 2 when irrigated with a salinity concentration of 48 dS·m−1 for 30 days, suggesting high salinity tolerance of ‘Riviera’. However, in this study, the normalized difference vegetation index (NDVI) had a lower ability to detect the increase in salinity stress due to the limited area measured by the NDVI measuring device used. An increase in sodium ion concentration was observed in the shoot with increasing salinity concentrations. The NDVI was highly correlated (r = 0.93) to LF, indicating the usefulness of NDVI as a tool to measure the magnitude of salinity stress. The multiple linear regression analysis revealed that the data showed a linear response to salinity stress with LF (r2 = 0.86) and NDVI (r2 = 0.76) decreasing linearly as the salinity concentration and days of treatment increased. This study provides an accurate depiction of the spectral and visual responses of ‘Riviera’ when exposed to multiple salinity concentrations with narrow increments.

Evaluation of teosinte derived maize lines for drought tolerance

Maize Plants grown in subtropical and temperate regions are often subjected to moisture stress. the wild progenitors of the crop species are the important source of genes of various abiotic and biotic stress tolerance. teosinte (Z. mays ssp. parviglumis), the progenitor of maize possesses several important genes of agronomic importance, majority of which were lost during the process of domestication. In the present investigation, 203 modern maize BC1F2 introgressed lines (encoded as am-1 to am-203) were developed and evaluated under irrigated and moisture stressed environments. In order to introduce the genes of agronomic importance from the progenitor teosinte to modern maize, DI-103 inbred were crossed with teosinte. the present study involved evaluation of 203 lines (encoded as am-1 to am-203). these lines were grown in a single row in two environmental conditions i.e. irrigated and stress condition during Rabi 2016–17 for the phenotyping of morpho-physiological traits viz., anthesis silking interval (ASI), leaf rolling, leaf firing, canopy temperature depression (CTD), chlorophyll content, ear length, ear diameter, kernel rows/ear, kernels/row, tip filling, grain filling, grain yield per plants (g), and 1000-kernel weight and drought tolerance index, stress tolerance index, yield index associated with drought tolerance. Overall sum of rank scores over thirteen traits associated with drought tolerance revealed that am-39 was the most drought tolerant line among all the 203 lines under study with a total score of one hundred eight, followed by am-64, am-16, am-42, and am-102, whereas, am-116 was the most susceptible, with the least score of thirty-four.

Detection of quantitative trait loci associated with drought tolerance in St. Augustinegrass.

St. Augustinegrass (Stenotaphrum secundatum) is a warm-season grass species commonly utilized as turf in the southeastern US. Improvement in the drought tolerance of St. Augustinegrass has significant value within the turfgrass industry. Detecting quantitative trait loci (QTL) associated with drought tolerance will allow for advanced breeding strategies to identify St. Augustinegrass germplasm with improved performance for this trait. A multi-year and multi-environment study was performed to identify QTL in a ‘Raleigh’ x ‘Seville’ mapping population segregating for phenotypic traits associated with drought tolerance. Phenotypic data was collected from a field trial and a two-year greenhouse study, which included relative water content (RWC), chlorophyll content (CHC), leaf firing (LF), leaf wilting (LW), green cover (GC) and normalized difference vegetative index (NDVI). Significant phenotypic variance was observed and a total of 70 QTL were detected for all traits. A genomic region on linkage group R6 simultaneously harbored QTL for RWC, LF and LW in different experiments. In addition, overlapping QTL for GC, LF, LW and NDVI were found on linkage groups R1, R5, R7 and S2. Sequence alignment analysis revealed several drought response genes within these regions. The QTL identified in this study have potential to be used in the future to identify genes associated with drought tolerance and for use in marker-assisted breeding.

Morpho-physiological traits associated with heat stress tolerance in tropical maize (Zea mays L.) at reproductive stage

Heat stress resilience has emerged as an important trait in maize hybrids targeted for post–monsoon spring cultivation in large parts of South Asia and many other parts of the tropics. Selection based on grain yield alone under heat stress is often misleading, and therefore an approach involving stress-adaptive secondary traits along with grain yield could help in the development of improved, stable heat stress tolerant cultivars. We attempted to identify reliable and effective secondary traits associated with heat stress tolerance in tropical maize and sources of heat stress tolerant germplasm. A panel of 99 elite maize inbred lines representing the wider genetic diversity of tropical maize and a set of 58 elite hybrids were phenotyped under natural heat stress and optimal temperature for grain yield and 15 secondary traits including 10 morpho-physiological traits and 5 yield attributes. Evaluation under natural heat stress was done during the spring season by adjusting the planting date so that the complete reproductive stage (from tassel emergence to late grain filling) was exposed to heat stress. The optimal temperature trial was planted during the monsoon season with no exposure to heat stress at any crop stage. Heat stress significantly affected most of the observed traits. Among the traits studied two yield attributing traits, i.e.- ears per plant (EPP) and kernel per row (KPR), and three morpho-physiological traits, i.e.- chlorophyll content (CC), leaf firing (LF) and tassel blast (TB) were found to be the key secondary traits associated with grain yield under heat stress. In addition, low anthesis-silking internal (ASI) is an important trait that needs to be added in the index selection for heat stress tolerance. The study identified nine promising heat stress tolerant maize inbred lines with desirable secondary traits and grain yield under severe heat stress, which could be used as source germplasm in heat stress tolerance maize breeding program.

Making Crops Climate Ready

Making Crops Climate Ready

Evaluation of physiological and growing behavior of warm season turfgrass species against salinity stress

The demand for salinity tolerant turfgrasses is increasing due to augmented use of effluent or low quality water for turf irrigation. Fresh water, coupled with soil salinization in many areas has resulted in an increased need for screening of salt-tolerant turfgrasses. Physiological responses to salinity and relative salt tolerance of four C4 turf grasses Cynodon dactylon (Bermuda grass), Zoysia matrella (Manilla grass), Stenotaphrum secundatum (St. Augustine grass) and Paspalum notatum (Bahia grass) were investigated during the study at Division of Floriculture and Landscaping, IARI, New Delhi 2015-2017. Turfgrasses were planted in plastic pots filled with sand: cocopeat: vermiculite (2:1:1) and irrigated with different concentration of salinity levels (50, 100, 200, 300, 400 and 500 mm). Salinity tolerance was evaluated on the basis of leaf firing, shoots and root growth reduction, proline content, total chlorophyll content and relative water content was subjected to analysis of variance. Among the four turfgrass species S. secundatum found to be most salt tolerant turf grass followed by Z. matrella while P. notatum was least tolerant turfgrass against salt stress.

Effects of foliar application of glycine betaine and chitosan on Puccinellia distans (Jacq.) Pari, subjected to salt stress.

Using brackish water for irrigation may expose turfgrasses to salinity stress. Employing the best treatments to maintain high-quality turfs under saline conditions is an important requirement for turfgrass management. We tested the response of a halophyte grass, Puccinellia distans, to irrigation with saline solutions and to foliar application of two osmoprotectants, such as glycine betaine (GB) or chitosan (CH). Plants were grown in pots under controlled conditions and irrigated with 200 mM or 600 mM of NaCl solutions. The response to salinity treatments and osmoprotectant application was evaluated after 90 days by measuring leaf firing, leaf density, shoot length and biomass, root length, and shoot water potential. Increasing salinity reduced shoot density, shoot and root length, shoot water potential, and increased leaf firing and shoot solute potential at 200 mM of NaCl. These effects were more pronounced at 600 mM of NaCl. Application of GB greatly increased shoot growth traits at 200 mM of NaCl and also showed beneficial effects on most traits at 600 mM. Application of CH showed positive effects only on leaf firing and leaf water potential at 600 mM. Our results show that P. distans can tolerate high levels of salt stress, which can be best alleviated by GB treatment.

Correlation and path coefficient analysis for grain yield and its attributing traits of maize inbred lines (Zea mays L.) under heat stress condition

Heat stress during the flowering, pollination and grain filling periods affect maize grain yield and its attributing traits. Twenty maize inbred lines were evaluated in alpha lattice design with two replications under heat condition during spring season from February to June, 2016 at Rampur, Chitwan, Nepal. Meterological data showed maximum mean temperature (46.2–43.28ºC) and minimum (30.52-30.77ºC) in with relative humidity 37.05 to 49.45% inside the tunnel during in April-May which coincided with the flowering, pollination and grain filling periods. The data were analyzed statistically to study the correlation and path coefficient. The analysis of variance showed that all the lines were significantly different from each other for all traits anthesis silking interval, SPAD chlorophyll and leaf senescence, tassel blast, leaf firing, plant and ear height, leaf area index, ear per plant, cob length and diameter, number of kernel ear-1, number of kernel row-1, number of kernel row, silk receptivity, shelling percentage, thousand kernel weight and grain yield. Grain yield had positive and significant phenotypic correlation with silk receptivity, shelling percentage, cob length and diameter, number of kernel ear-1, number of kernel row-1, number of kernel row, SPAD chlorophyll, thousand kernel weight and significant and negative correlation with tassel blast, anthesis silking interval, leaf area index, leaf firing. Path analysis revealed that of thousand kernel weight, shelling percentage, number of kernel ear-1 and silk receptivity exerted maximum positive direct effect on grain yield. Therefore, selection of genotypes having maximum thousand kernel weight, shellingpercentage, silk receptivity and number of kernel ear-1 and shorter anthesis silking interval, no leaf firing and tassel blast is pre-requisite for attaining improvement in grain yield under heat stress condition.

Genetic Mapping of Foliar and Tassel Heat Stress Tolerance in Maize

The frequency of heat stress events is expected to increase, further complicating the challenge of feeding a growing population. A better understanding of the genetic and molecular mechanisms of heat stress tolerance in maize (Zea mays L.) would facilitate the development of heat‐tolerant cultivars. To address this knowledge gap, we evaluated two biparental recombinant inbred line (RIL) populations (B73 × NC350 and B73 × CML103) for leaf and tassel heat tolerance traits. Two foliar traits, leaf firing and leaf blotching, were evaluated at three vegetative growth stages. In B73 × NC350, two tassel traits, tassel blasting and reduction in spikelet size, were scored at flowering. We detected 22 quantitative trait loci (QTL), 15 in B73 × NC350 and seven in B73 × CML103. We previously observed that the development of leaf firing was differentiable between parents, and indeed, the different manifestations of the leaf firing trait were not significantly correlated and QTL did not co‐localize. Leaf firing and leaf blotching traits were correlated at some vegetative growth stages, and most QTL did not co‐localize. Quantitative trait loci number and position for traits measured at multiple vegetative stages were generally consistent. There was a single QTL for tassel blasting on chromosome 5. Heat‐induced plant death segregated in B73 × CML103 and a major QTL was detected on chromosome 3, explaining 26.2% of phenotypic variance. Our study indicates that complex genetic mechanisms underlie the heat stress response in maize.

The Salinity Tolerance of Seeded-type Common Bermudagrass Cultivars and Experimental Selections

Turfgrass managers are using reclaimed water as an irrigation resource because of the decreasing availability and increasing cost of fresh water. Much attention, thereby, has been drawn to select salinity-tolerant turfgrass cultivars. An experiment was conducted to evaluate the relative salinity tolerance of 10 common bermudagrasses (Cynodon dactylon) under a controlled environment in a randomized complete block design with six replications. ‘SeaStar’ seashore paspalum (Paspalum vaginatum) was included in this study as a salinity-tolerant standard. All entries were tested under four salinity levels (1.5, 15, 30, and 45 dS·m−1) consecutively using subirrigation systems. The relative salinity tolerance among entries was determined by various parameters, including the normalized difference vegetation index (NDVI), percentage green cover determined by digital image analysis (DIA), leaf firing (LF), turf quality (TQ), shoot vertical growth (VG), and dark green color index (DGCI). Results indicated that salinity tolerance varied among entries. Except LF, all parameters decreased as the salinity levels of the irrigation water increased. ‘Princess 77’ and ‘Yukon’ provided the highest level of performance among the common bermudagrass entries at the 30 dS·m−1 salinity level. At 45 dS·m−1, the percent green cover as measured using DIA varied from 4.97% to 16.11% among common bermudagrasses, where ‘SeaStar’ with a DIA of 22.92% was higher than all the common bermudagrass entries. The parameters LF, TQ, NDVI, DGCI, VG, and DIA were all correlated with one another. Leaf firing had the highest correlation with other parameters, which defined its value as a relative salinity tolerance measurement for common bermudagrass development and selection.

Analysis of genetic diversity among the maize inbred lines (Zea mays L.) under heat stress condition

High temperature adversely affects the plant physiological processes: limits plant growth and reduction in grain yield. Heat stress is often encountered to spring sowing of maize in spring season. Twenty maize inbred lines were studied for days to 50 % anthesis and silking, anthesis–silking interval, leaf firing, tassel blast, SPAD reading and leaf senescence, plant and ear height, leaf area index, ear per plant, cob length and diameter, number of kernel/ear, number of kernel row/ear, number of kernel row, silk receptivity, shelling percentage, thousand kernel weight and grain yield in alpha lattice design at National Maize Research Program at Rampur, Chitwan,Nepal with the objective to identify superior heat stress tolerant lines. Analysis of variance showed significant difference for all the traits. Result of multivariable analysis revealed that twenty inbred lines formed four clusters. The resistance inbred lines and susceptible inbred lines formed different clusters. The members of cluster 4 were found to be tolerant to heat stress due to they had lowest value of tassel blast, leaf firing, and leaf area index with highest value of cob diameter and length, ear per plant, number of kernel row/ear, number of kernel/ear, number of kernel row, shelling percentage, silk receptivity and grain yield whereas as members of cluster 1were found most susceptible due to they had longer anthesis silking interval, with maximum tassel blast and leaf firing along with no grain yield under heat stress condition. From this study inbred lines RL-140, RML-76, RML-91 and RML-40 were found most tolerant to heat stress. These inbred lines belonging to superior cluster could be considered very useful in developing heat tolerant variety and other breeding activities.

Impact of wastewater irrigations and planting methods on leaf firing, colour, quality and traffic tolerance of turfgrass

Impact of wastewater irrigations and planting methods on leaf firing, colour, quality and traffic tolerance of turfgrass