No abstract

Rapid increase in population and consumption, urged upon the agronomists to develop a comprehensive site specific agro technology to boost up production per unit area and quality of daily dietary onion crop in salt affected soils by improving some basic components of the prevailing onion production technology in Pakistan. In this perspective a detailed and systematic series of field studies were undertaken for three consecutive years (2013 -2015) at Soil Salinity Research Institute, Pindi Bhattian, Pakistan to evaluate different nitrogen levels and the cost-effective planting technique for onion production under salt affected conditions. The experiment was laid out in split plot arrangement using randomized complete block design having three replications. Two planting methods, ridge and bed planting and 4 nitrogen levels, 1-recommended dose (RD) of N (90 kg ha -1 ), 2 -75 % N of RD (67.5 kg ha -1 ), 3 -125 % N of RD (112.5 kg ha -1 ), 4 -150 % N of RD (135 kg ha -1 ) were used. Planting methods were kept in main plots and nitrogen levels in sub plots keeping sub-plot size of 4 m x 6 m. Measurements included were: plant height, number of leaves/plants/m -2 , bulb diameter, bulb mass, total bulb yield, number of flowers/umbel, seed mass/plant and 1000-seed mass. Results showed that maximum onion yield and yield attributes were recorded with nitrogen application at rate of 150 & 125 of RD in ridge planting. However nitrogen application at rate of 125 of RD in ridge planting recorded higher economic returns over all the other treatments and is recommended as most cost effective technique for onion production under salt affected soil as compare to other treatments. . Obravnavanja z načini sadnje so bila na glavnih ploskvah, obravnavanja gnojenja z N pa na podploskvah velikost 4 m x 6 m. Meritve so obsegale višino rastlin, število listov/rastlino/m 2 , premer čebule, maso čebul, celokupni pridelek čebul, število cvetov na kobul, maso semena na rastlino in maso 1000 semen. Rezultati so pokazali največji pridelek čebule in njegovih delov pri obravnavanjih z dušikom 150 in 125 % od priporočene doze (RD) in pri sadnji na grebene. Pri tem je obravnavanje z dušikom 125 % od priporočene doze in sadnja na grebene dalo največji ekonomski učinek v primerjavi z drugimi in ga priporočamo kot stroškovno najbolj učinkovit način pridelave čebule v razmerah zasoljenih tal.Ključne besede: čebula; dušikova gnojila; načini sadnje; slanost; analiza stroškov in koristi

Deficiency of phosphorus can reduce the yield up to 15-20% and its availability to crop plants is the main issue, particularly in calcareous soils of Pakistan. Micro-organisms, phosphorus solubilizing bacteria (PSB) and sulphur oxidizing bacteria (SOB) have the ability to make P accessible for optimum plant growth, under conditions of nutrients disparity. Therefore, six treatments i.e. control, Yz dose of NPK, full recommended dose of NPK, Yz NPK+ SOB, Yz NPK + PSB and Yz NPK + SOB+ PSB were applied in a field experiment to investigate the integrated role of SOB and PSB with NPK fertilizers for enhancing the maize production. The treatment was concluded to have major impact on agro-morphological traits, seed quality and growth parameters of maize. Results depicted that the use of Yz NPK + SOB + PSB gave maximum germination count/plot (151.33), plant height (189.03 cm), number of ears/plant (1.60), grains/ear (472.33), 1000-grain weight (305.67 g), grain yield (5350.50 Kg/ha), harvest index (31.23%), leaf area (379.77 cm2), total dry matter accumulated (181.43 g/plant), crop growth rate (30.60 g/day), net assimilation rate (9.31 g/day) and protein contents (8.49%).  

Oxidative stress due to salinity creates a challenging situation for seed germination and early seedling establishment in maize. Over than normal production of reactive oxygen species (ROS) leaves cataclysmic effects on the physiology of plants when subjected to saline environment. Melatonin is versatile stress mitigating organic molecule reported to have significant potential for scavenging ROS. The present study was conducted with the aim to study the effects of different concentrations of melatonin viz., control, 500, 1000 & 1500 µM on the physiological and bio-chemical stress markers in the six maize genotypes viz., MMRI-Yellow, NCEV-1530-9, YH-1898, Composite, SB-9617 and FH-949.The study was planned in sand culture (pot study) using CRD with factorial arrangement. The results of the present study demonstrated that melatonin priming in all the concentrations viz., 500,1000 and 1500µM significantly enhanced the germination percentage (by 14.0 , 25.0 and 27 %), chlorophyll a (23.3, 43.3 & 40.0 %), chlorophyll b contents (by 29.2, 50.0 & 50.0 %), total soluble sugar-TSS (by 20.0, 31.5 & 40.4 %), total soluble protein-TSP (by 10.0, 15.5 & 20.5%), chlorophyll stability index-CSI (by 15.0, 20.3 & 25.6%), membrane stability index-MSI (13.3, 25.7 & 26.6%), relative water contents-RWC (13.7, 23.3 & 24.0%), phenolic contents-TP (14.8, 24.3 & 26.8 %), proline contents-Pro (23.0, 35.2 & 37.7%), superoxide dismutase-SOD (by 25.5, 41.0 & 45.0 %), per-oxidase-POD (by 17.8, 25.1 & 24.7%), catalase-CAT (by 37.7, 51.5 & 54.3%) and reduced concentrations of H2O2 (by19.3, 26.5 & 30.1 %), malondialdehyde-MDA contents (by 15.1, 22.4 & 22.3%) and electrolyte leakage-EL (by 12.4, 18.0 & 16.5 %), compared to un-primed seed treatment. Interestingly the higher concentrations of melatonin were statistically produced the same effects. The genotype SB-9617outperformed, with respect to higher accumulation of photo-pigments, TSS, TSP and TP with improved of membrane stability, relative water contents and enhanced activities of the anti-oxidant enzymes (SOD, POD and CAT) showed reduced lipid per-oxidation and electrolyte. In PCA-bi-plot, PC1 and PC2 contributed maximally i.e. 90.9 and 3.7% to explain the total variations i.e 94.6 %. Additionally, SB-9617 with melatonin priming@ 1000µM proved the best to mitigate adverse effects of salt stress at germination and early seedling growth stage via cross taking with physiological and bio-chemical stress markers.

Maize crop is the third most important cereal crop, mostly grown for food, feed and fodder purpose. In spite of the fact the crop is susceptible to salt stress but exhibits a considerable genotypic variability for salt tolerance. The present study was carried out to determine to which extent the maize genotypes with contrasting morphological traits respond to salt stress. Seven days old seedlings of thirty maize genotypes were exposed to NaCl stress of EC less than 4 (control), equal to 8 and 12 dS m-1 for further 28 days in a temperature controlled greenhouse. The salt stress imposition was completed in two increments every other day from the date of planting. At the age of 35 days, the seedlings were evaluated for contrasting morphological traits. The genotypes exhibited considerable variations for each of the 10 measured morphological and ionic traits. PCA was employed to identify the most suitable morphological trait to be used as selection criterion for salt tolerance. Based on the PCA results, dry shoot weight (DSW) was used to classify thirty maize genotypes into salt-tolerant-T, moderately tolerant-MT and salt sensitive-S groups. Two (2) out of thirty genotypes i.e. SB-9617 and FH-949 had the highest average of percent dry shoot weight (PDSW) values > 70%  were classified as salt tolerant (T). The fifteen (15) genotypes showed average of PDSW values in the range of 55-69.9 % were classified as moderately tolerant (MT) by indicating the sequence order of salt tolerance as YH-1898 > MMRI-yellow > S-2002 > FH-988 > FH-1292 > HC-12 > MS-2018 > NCEV-1270-7 > Pahari > Pearl White > FH-1114 > NCEV-1270-3 > Iqbal > NCEV-1297 > DK-6724. However, thirteen (13) out of total thirty (30) genotypes attained the average PDSW values <55% were classified as salt sensitive (S) following the sequence order as NCEV-1530-9 > Composite > FRI-22 > Azam > MS-2015 > P-1543 > Neelum > Afgoi > Malka-2016 > MS-1501 > HNG > NCEV-1270-5 > NCEV-7004. It was also noticed that the declared salt tolerance was positively correlated with dry shoot weight (DSW), shoot length (SL), stem diameter (SD), fresh shoot weight (FSW), fresh root weight (FRW), dry roots weight (DRW), root length (RL), leaf area per plant (LA), number of leaves per plant (NL) and K+/Na+ ratio. The highest positive Pearson correlation coefficients were determined in LA vs SD (r=0.900), DSW vs SD (r=0.899), SL vs DSW (r=0.891), SL vs FSW (r=0.890) and DSW vs FSW (r=0.887). Additionally, the salt tolerant (T) group of genotypes maintained higher K+/Na+ ratios compared to moderately tolerant (MT) and salt sensitive (S) groups. The results clearly showed that dry shoot weight (DSW) could be viable option to classify maize genotypes into different salt tolerance groups and to identify the most suited and best adapted salt tolerant genotype for cultivation in saline soils. Furthermore, this scientific information could help the plant scientists to improve and develop the new salt tolerant cultivar.