To refine selection methods for a perennial ryegrass (Lolium perenne L.) breeding program, half-sib families and commercial cultivars were evaluated for 3 years with treatments sown as both single-drill rows or swards. Dry matter yield of the perennial ryegrass treatments was evaluated several times in each year as a visual score which was subsequently calibrated against a regression determined by cutting a subset of plots or by cutting all plots. Thus, the experiment evaluated 2 aspects of herbage-yield determination in a perennial ryegrass breeding program: (i) the use of visual estimates of herbage yield to reduce the time spent cutting plots, and (ii) the use of single-row plots compared with swards. The correlation (either as Pearsons correlation coefficient, or Spearmans rank correlation coefficient) between visual estimates of herbage yield was always significant (P<0.01), with the exception of the rank correlation for sward plots in the summer 1995 (r = 0.4; P<0.05). However, the extent of the correlation varied (r = 0.4–0.9), and at some harvests calibrated visual ratings only explained a small proportion of the variance observed in harvested dry matter yields. These data suggest that visual ratings of herbage yield would be accurate enough to be used to detect large differences between families, breeding lines, cultivars or accessions of perennial ryegrass. However, when differences between lines are likely to be small, then harvesting all plots would give a more accurate estimate of the yield of perennial ryegrass lines. Likewise, the herbage yield of perennial ryegrass in single-row plots was significantly correlated with the herbage yield of perennial ryegrass sown as swards (P<0.01 or P<0.05). However, the correlation was again variable leading to the conclusion that evaluation of perennial ryegrass as single-row plots was not always an accurate indicator of sward yield. For those 4 (of 13) harvests over 3 years where the interaction between sward yield and row yield of the perennial ryegrass lines was significant (P<0.05), this interaction was shown not to be due to significant rank changes but rather to an increase in the differences of yield in swards or yield in single-row plots. We conclude that the harvesting of swards was the most reliable method of estimating the dry matter yield of perennial ryegrass cultivars. However, significant correlations between visual rating of treatments, or yield in single-row plots and measured yield as swards illustrated that these methods (visual ratings and single-plot yields) could be used to reduce the cost of evaluating differences in the herbage yield potential of perennial ryegrass, especially when these differences were likely to be large or when seed is limited, such as during the evaluation of accessions.

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Nutritious management in fine rice is primarily concomitant with the application of nitrogen and zinc fertilizers, which is challenging to amend under field conditions due to variations in soil fertility and environmental conditions. Therefore, a field experiment was carried out at Chakkanwali reclamation Research Station district Gujranwala to explore the role of nitrogen and zinc on the growth and yield of fine rice during kharif 2016. This study was laid out in a randomized complete block design with factorial arrangement having three repeats. Experimental treatments comprised of 2% foliar spray of nitrogen and zinc at tillering, booting, and flowering stage alone and in combinations. Results indicated that exogenous application of 2% nitrogen and zinc at flowering stage significantly improved all the yield contributing parameters which ultimately enhanced the final paddy yield.

Wheat crops are highly sensitive to high temperatures during their reproductive and grain-filling phases. We hypothesized that potassium could increase thermotolerance in wheat during grain filling by protecting cellular organelles, particularly chlorophyll, from heat injury. Two wheat genotypes, Ujala-16 (relatively heat tolerant) and Anaj-17 (relatively susceptible) were grown in pots and were submitted to 4 and 8 days of heat stress under polythene sheets 1 week after anthesis. One day before the onset of heat stress, 2% potassium (K) as K2SO4 was sprayed on all the plants. Flag leaves from both genotypes were collected after 4 and 8 days of heat stress. Leaf physiology changes were measured to quantify heat damage and to understand the K-induced recovery mechanism. The crop was harvested 125 days after sowing, and grain yield data were collected. Increasing duration of heat stress significantly impaired leaf physiology and grain yield of both studied wheat genotypes. Compared with control (under optimum temperature), 4 and 8 days heat-stressed plants produced 11 and 19% lesser grain yield per spike (averaged across genotypes and in the second years of study), respectively. Likewise, 4- and 8-days heat-stressed plants had 15 and 37% (averaged across genotypes and in the second years of study) lower flag leaf photosynthesis, respectively, compared with control plants. Across the genotypes, 8-days heat caused significantly more grain yield loss in Anaj-17 during the second year than in Ujala-16. Foliar K significantly restored leaf chlorophyll, Pn, Fv/Fm by reducing cellular membrane damage in the heat-stressed plants. This physiological recovery and activation of the plant defensive system by K under high-temperature stress protected the growth and grain development. For example, K–treated plants produced 19% higher 1,000 grain weight in 8 days of heat stress (across genotypes and in the second years of study) compared with water-treated plants under the hot environment of the respective thermal regime. Our study suggests that wheat performance under terminal heat stress can be improved through the exogenous application of K.