In order to study the effect of salts stress on the growth and yield of wheat (cv. Inqalab), a pot experiment was conducted in the wire-house of the Department of Soil Science, Sindh Agriculture University Tando Jam. The soil was artificially salinized to a range of salinity levels i.e. EC 2.16, 4.0, 6.0, 8.0 and 10.0 dS•m −1 with different salts (MgCl 2 + CaCl 2 + Na 2 SO 4). The salinized soil used for the experiment was sandy clay in texture, alkaline in reaction (pH > 7.0) and moderate in organic matter (0.95%) content. The results showed that with increasing salinity there was an increase in the ECe, Na + , Ca 2+ , Mg 2+ and Cl − and decrease in the K + , SAR and ESP values of the soil Increasing salinity, progressively decreased plant height, spike length, number of spikelets spike −1 1000 grain weight and yield (straw and grain). Adverse effects of salts on plants were associated with the accumulation of less K + and more Na + and Cl − in their flag leaf sap, grains and straw. This resulted in lower K + :5Na + ratio in flag leaf sap, grains and straw of wheat plants. These results indicated that the effects of salts stress were greater at 10 than at 8, 6 and 4 EC dS•m −1 .

Cotton is one of the most important fibre crops playing a key role in economic and social affairs of the world. Water is a critical factor which influences on growth and yield of the cotton crop. Scarcity of water has put tremendous pressure on scientists to introduce drought tolerant cotton varieties. This study was aimed to determine water stress effects on the growth and yield of cotton. The present study was carried out to examine the effect of number of irrigations on the growth and yield of cotton during 2014. The field trial was conducted at the Experimental Fields of Agronomy Section, Agriculture Research Institute, Tandojam, Pakistan. A three replicated Randomized Complete Block Design (RCBD) was employed to layout the experiment having plot size of 2.5 m × 5 m (12.5 m 2). Four cotton varieties i.e. NIAB-78, Shahbaz-95, Sindh-1 and TH-224/87 were chosen for this study based on their frequent farmer usage. All the agronomic practices were performed according to standard procedures. Results showed that all the growth and yield components of cotton were significantly (P < 0.01) affected by varieties and irrigation frequencies with exception of monopodial branches and staple length, which were not significantly (P > 0.05) affected by irrigation frequencies. The cotton crop irrigated six times at 21 days interval showed better results with 138.16 cm plant height, 1.45 monopodial branches per plant, 21.83 sympodial * Corresponding author. A. Sahito et al. 1028 branches per plant, 44.58 bolls per plant, 33.86% G.O.T., and 26.97 mm staple length, 149.84 g seed cotton yield per plant and 2271.16 kg•ha −1 seed cotton yield. This study concluded that variety NIAB-78 showed superiority over Shahbaz-95, Sindh-1 and TH-224/87 in almost all the characters of economic importance, and the cotton crop received 6 irrigations at 21 days interval resulted in significantly economical overall performance as compared with 5 irrigations or 4 irrigations with higher seed cotton yield.

The present research work was carried out at Southern Wheat Research Station, Tandojam during the growing season 2013-14 in order to work out correlation and regression analysis for yield traits in wheat genotypes. The experiment was laid out in a Randomized Complete Block Design with three replications. Eight bread wheat genotypes such as Mehran, Sarsabz, TJ-83, SKD-1, Inqlab, A. Sattar, Sehar and Sassui were used to examine correlation and regression. Seven traits, viz.; plant height, tillers plant −1 , spike length, spikelet's spike −1 , grains spike −1 , seed index and grain yield plant −1 were studied. The analysis of variance revealed significant differences among the genotypes for plant height, tillers plant −1 , spike length, spikelet's spike −1 , grains spike −1 , seed index and grain yield plant −1. Based on mean performance, variety Sarsabz gave maximum plant height (95.46), produced maximum tillers plant −1 (4.40), gave more grain spike −1 (63.13), TJ-83 gave highest seed index (47.260), and was next ranker in spike length −1 (12.07), spikelet's spike −1 (19.13), grains spike −1 (59.86), and grain yield plant −1 (9.86) among the genotypes. The phenotypic correlations revealed that tillers plant −1 and grains spike −1 were highly positively associated; hence these yield components can be used as reliable selection criteria to improve grain yield in wheat. Thus estimation of correlation and regression analysis among yield and yield components may provide effective selection criteria to improve wheat grain yield. The results from correlation and regression of plant height indicated significantly positive association with spikelet's spike −1 , tillers plant −1 and grains spike −1 which revealed that increase in plant height will cause corresponding increase in associated traits.

The heterosis, heterobeltiosis, general combining ability (GCA) and specific combining ability (SCA) were examined during Rabi (crop season) of 2013-2014 in hexaploid wheat genotypes. The experiment for this study was conducted at the Botanical Garden, Department of Plant Breeding & Genetics, Sindh Agriculture University Tandojam, Pakistan. The breeding material was comprised of four parents (Imdad, TD-1, SKD-1, and Moomal). These parents were crossed in half partial mating fashion; thus, six possible cross combinations (F1s) were obtained (Imdad × TD-1, Imdad × SKD-1, Imdad × Moomal, TD-1 × SKD-1, TD-1 × Moomal, and SKD-1 × Moomal). A three-replicated RCB Design was used. The mean squares corresponding to different traits of various hexaploid wheat genotypes indicated significant (P < 0.01) GCA (parents) and SCA (F 1 hybrids) effects for the characters (plant height, tillers plant −1 , spike length, spikelets spike −1 , seeds spike −1 , seed index, and grain yield plant −1). The mean performance of F 1 hybrids differed significantly (P < 0.01) for all the traits studied. Among the parents, Imdad and TD-1 proved to be better general combiners for almost all the studied traits. In regards to SCA effects, the F 1 hybrids Imdad × TD-1 and Imdad × SKD-1 expressed higher SCA and heterotic effects for most of the studied traits.

Nitrogen fertilizer is one of the key elements to increase the yield and significance of winter wheat. The experiment was established in the split zone design and was repeated three times. The nitrogen application level is set to 4 treatments, 75, 150, 225 and 300 kg ha −1 are arranged in the main plot, and different nitrogen application ratios are arranged in the sub-plots, respectively 5:5 (50%+50%) and 6: 4 (60%) + 40%). Nitrogen fertilizer was applied before sowing, jointing stage, flowering stage and filling stage. The experimental plot is 12 m2 (3 m × 4 m). The results showed that under the conditions of 225 kg/hm2 nitrogen application and 60%+40% nitrogen application rate, the yield of Jintai 182 was the highest compared with other treatment groups. With the increase of nitrogen application rate, the number of ears, grains per ear, thousand-grain weight and grain yield all increase first and then decrease. Each factor reached the highest 225 N kg / hm2, 417.17, 30.74, 40.96 g and 6182.11 kg / hm2. Compared with 75 kg/hm2 topdressing fertilizer, 225 kg/hm2 is a more suitable nitrogen fertilizer application rate for winter wheat. Within a reasonable range of nitrogen fertilizer application, there is a significant positive correlation between nitrogen content and winter wheat yield. By studying the amount of nitrogen fertilizer and a reasonable ratio of base fertilizer to topdressing, the utilization rate of nitrogen fertilizer can be maximized and excessive application of nitrogen fertilizer can be avoided.