scholarly journals Studying Maize Growth Indices in Different Water Stress Conditions and the Use of Humic Acid

2017 ◽  
Vol 10 (1) ◽  
pp. 303-310 ◽  
Author(s):  
Parisa sharifi
2017 ◽  
Vol 10 (01) ◽  
pp. 303-310
Author(s):  
Parisa sharifi

An experiment was conducted in split plots in a completely randomized block design with three replications to evaluate the impact of drought stress on physiological indices of maize growth and the effect of humic acid fertilizer on alleviating drought stress. The main factor included three irrigation levels of 100%, 75%, and 50% and sub-factor was the use and non-use of humic acid. The results showed that in all different levels of irrigation and humic acid treatments, the index of leaf area index (LAI), crop growth rate (CGR) and dry matter accumulation are sigmoid. The highest LAI was (4.5) and biological yield was (15.5 ha) in full irrigation treatment with humic acid, and minimum LAI was (3) with biological yield (8.8 tons per hectare) in 50% irrigation treatment and non-use of humic acid. The results showed that LAI and receiving light were the most important factor affecting the growth indices. Moreover, the highest and lowest CGR CGR, relative growth rate (RGR) RGR and net absorption rate (NAR) were related to full irrigation + consumption of humic acid and 50% irrigation and non-use of humic acid respectively. Overall, the results showed that in without stress treatment (irrigation 100%), the use of humic acid compared to non-use increased RGR, CGR, NAR and LAI at 1.3%, 21%, 8% and 12.5% respectively. This is while in water stress (irrigation 50%), humic acid consumption increased these indices 7%, 25%, 14% and 30% respectively representing a reduction drought stress by humic acid. In general, it could be argued that the use of humic acid, due to adjusting the drought, could have a positive role in water stress to reduce the use of chemical fertilizers, reducing environmental pollution, and to mitigate drought stress, and as is suggested a stable source of supplying nutrients in drought conditions for maize.


Author(s):  
F Shafique ◽  
Q Ali ◽  
A Malik

Many biotic and abiotic factors affect plant growth and its development. Maize growth usually increased under excess water availability but less tolerant against water deficit stress condition. In this study, we investigated the effects of water stress on the growth and yield of maize. We found that severe water stress during the seedling stage had a greater effect on the growth and development of maize. Three maize varieties (Pak afghoi, Neelum, White corn) were used to find out the effects on growth of plant under drought or water deficit environmental conditions. Different drought stress treatments (Control, 20% irrigation water, 40% irrigation water, 60% irrigation water, 80% irrigation water) were imposed to growing seedlings after germination. The treatments were applied after 4 times each after 7 days interval and data for different morphological traits was recorded each time. The recorded data was pooled and analyzed for analysis of variance to access the significance of results. The ANOVA indicated the differences among five different genotypes and 5 different treatments for all parameters were significant. Tukey’s test indicated that maize genotype White corn was more tolerant while genotype Neelum was more sensitive for drought stress conditions therefore, white corn maize genotype may be helpful for the development of drought tolerance maize varieties and hybrids. Positive and significant correlation was found for shoot length with all other studied traits under drought stress conditions. Treatment control, 80% and 60% irrigation water was less adverse for maize growth while treatment 20% irrigation water highly affected all maize genotypes, therefore maize genotypes may be grow under treatment 60% irrigation water.


2021 ◽  
pp. 1-22
Author(s):  
Amanullah ◽  
Mohammad Yar ◽  
Shah Khalid ◽  
Mohamed Soliman Elshikh ◽  
Hafiz M. Akram ◽  
...  

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Mahmoud M. Gaballah ◽  
Azza M. Metwally ◽  
Milan Skalicky ◽  
Mohamed M. Hassan ◽  
Marian Brestic ◽  
...  

Drought is the most challenging abiotic stress for rice production in the world. Thus, developing new rice genotype tolerance to water scarcity is one of the best strategies to achieve and maximize high yield potential with water savings. The study aims to characterize 16 rice genotypes for grain and agronomic parameters under normal and drought stress conditions, and genetic differentiation, by determining specific DNA markers related to drought tolerance using Simple Sequence Repeats (SSR) markers and grouping cultivars, establishing their genetic relationship for different traits. The experiment was conducted under irrigated (normal) and water stress conditions. Mean squares due to genotype × environment interactions were highly significant for major traits. For the number of panicles/plants, the genotypes Giza179, IET1444, Hybrid1, and Hybrid2 showed the maximum mean values. The required sterility percentage values were produced by genotypes IET1444, Giza178, Hybrid2, and Giza179, while, Sakha101, Giza179, Hybrid1, and Hybrid2 achieved the highest values of grain yield/plant. The genotypes Giza178, Giza179, Hybrid1, and Hybrid2, produced maximum values for water use efficiency. The effective number of alleles per locus ranged from 1.20 alleles to 3.0 alleles with an average of 1.28 alleles, and the He values for all SSR markers used varied from 0.94 to 1.00 with an average of 0.98. The polymorphic information content (PIC) values for the SSR were varied from 0.83 to 0.99, with an average of 0.95 along with a highly significant correlation between PIC values and the number of amplified alleles detected per locus. The highest similarity coefficient between Giza181 and Giza182 (Indica type) was observed and are susceptible to drought stress. High similarity percentage between the genotypes (japonica type; Sakha104 with Sakha102 and Sakha106 (0.45), Sakha101 with Sakha102 and Sakha106 (0.40), Sakha105 with Hybrid1 (0.40), Hybrid1 with Giza178 (0.40) and GZ1368-S-5-4 with Giza181 (0.40)) was also observed, which are also susceptible to drought stress. All genotypes are grouped into two major clusters in the dendrogram at 66% similarity based on Jaccard’s similarity index. The first cluster (A) was divided into two minor groups A1 and A2, in which A1 had two groups A1-1 and A1-2, containing drought-tolerant genotypes like IET1444, GZ1386-S-5-4 and Hybrid1. On the other hand, the A1-2 cluster divided into A1-2-1 containing Hybrid2 genotype and A1-2-2 containing Giza179 and Giza178 at coefficient 0.91, showing moderate tolerance to drought stress. The genotypes GZ1368-S-5-4, IET1444, Giza 178, and Giza179, could be included as appropriate materials for developing a drought-tolerant variety breeding program. Genetic diversity to grow new rice cultivars that combine drought tolerance with high grain yields is essential to maintaining food security.


2018 ◽  
Vol 40 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ayslan Trindade Lima ◽  
Paulo Henrique de Jesus da Cunha ◽  
Bárbara França Dantas ◽  
Marcos Vinicius Meiado

Abstract: Seed hydration memory is the ability of seeds to retain biochemical and physiological changes caused by discontinuous hydration. This study aimed to determine if Senna spectabilis (DC.) H.S. Irwin & Barneby var. excelsa (Schrad.) H.S.Irwin & Barneby (Fabaceae) present seed memory and evaluate the effects of hydration and dehydration cycles (HD) on the seed germination of this species when submitted to conditions of water stress. Seeds underwent HD cycles (0, 1, 2 and 3 cycles) corresponding to the hydration times X (6 hours), Y (16 hours) and Z (24 hours), determined from the imbibition curve, with 5 hours of dehydration and submitted to water stress conditions. Germination was evaluated at 0.0, -0.1, -0.3, -0.6 and -0.9 MPa, obtained with polyethylene glycol 6000 solution. Germinability (%), mean germination time (days) and hydrotime (MPa d-1) were calculated. The seeds of S. spectabilis var. excelsa are sensitive to the low osmotic potentials tested in this study, however, when submitted to the HD cycles of 16 hours hydration (time Y), the tolerance to water stress conditions is increased. In addition, the observed benefits on the evaluated germination parameters show that S. spectabilis var. excelsa present seed hydation memory.


OENO One ◽  
2013 ◽  
Vol 47 (4) ◽  
pp. 269 ◽  
Author(s):  
Edoardo Antonio Costantino Costantini ◽  
Alessandro Agnelli ◽  
Pierluigi Bucelli ◽  
Aldo Ciambotti ◽  
Valentina Dell’Oro ◽  
...  

<p style="text-align: justify;"><strong>Aim</strong>: To evaluate the relationship between carbon isotope ratio (δ<sup>13</sup>C) and wine grape viticultural and oenological performance in organic farming.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The study was carried out for four years in the Chianti Classico wine production district (Central Italy), on five non irrigated vineyards conducted in organic farming. The reference variety was Sangiovese. Eleven sites were chosen for vine monitoring and grape sampling. The performance parameters were alcohol and must sugar content, sugar accumulation rate, mean berry weight, and extractable polyphenols. δ<sup>13</sup>C, stem water potential, and soil water availability were also monitored. Finally, soil nitrogen as well as yeast available nitrogen in the must were measured. δ<sup>13</sup>C was directly related to stem water potential and soil water deficit, and indicated a range of water stress conditions from none and moderate to strong. However, its relationship with viticultural and oenological results was contrary to expectation, that is, performance linearly increased along with soil moisture. On the other hand, the worst performance was obtained where both water and nitrogen were more limiting.</p><p style="text-align: justify;"><strong>Conclusions</strong>: The unexpected relationship between δ<sup>13</sup>C and Sangiovese performance was caused by low nitrogen availability. The studied sites all had low-fertility soils with poor or very poor nitrogen content. Therefore, in the plots where soil humidity was relatively higher, nitrogen plant uptake was favoured, and Sangiovese performance improved. Macronutrient being the main limiting factor, the performance was not lower in the plots where soil water availability was relatively larger. Therefore, the best viticultural result was obtained with no water stress conditions, at low rather than at intermediate δ<sup>13</sup>C values.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: Water nutrition is crucial for wine grape performance. δ<sup>13</sup>C is a method used to assess vine water status during the growing season and to estimate vine performance. A good performance is expected at moderate stress and intermediate δ<sup>13</sup>C values. A better knowledge of the interaction between water and nutrient scarcity is needed, as it can affect the use of δ<sup>13</sup>C to predict vine performance.</p>


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