Total Yield Variation Research Articles

Formation of planned potato yield in the conditions of the Souther Urals

The most important factor for obtaining planned potato yields in rainfed farming in the forest-steppe zone of Chelyabinsk region is the availability of moisture. The yield of tubers depends on the weather conditions of the growing season by 18.7%, the density of crops - by 17.3%, varieties - by 8.4% and the use of microfertilizer Forsage by 5.1%. The level of balanced nutrition determines 46.2% of total potato yield variation and is the main factor. The yields of the studied varieties under the conditions of 2019 (HTC = 0.91) was 1.15-1.23 times higher than in 2020 (HTC = 0.85) and 1.25-1.67 times more than in the drought conditions of 2021 (HTC = 0.39). Dense planting of potatoes ensured an increase in the yield of tubers and did not affect the content of starch in the tubers. The microfertilizer Forsage increased the yield of the variety Zakhar by an average of 2.5 t/ha, Rosara - by 2.1 t/ha, Kashtak - by 2.5 t/ha compared to the control. The influence of Forsage on the starch content of tubers depended on the variety and density. The best result is provided by a combination of a dense planting, the use of varieties Zakhar and Kashtak and the use of microfertilizer Forsage.

Genotype × environment interaction and stability analyses of grain yield in rainfed winter bread wheat

Abstract The genotype × environment (GE) interaction analysis is fundamental in crop breeding programs to guide selection and for recommendation of high performing and stable genotypes for breeding objectives. This study aimed at quantifying the GE interaction effects and determines grain yield stability among winter bread wheat genotypes under rainfed conditions of Iran. Twenty-four winter wheat genotypes were evaluated under nine test locations using a randomized complete blocks design with four replications during three cropping seasons (2019–21). The additive main effects and multiplicative interaction (AMMI) model and several parametric and nonparametric stability statistics were applied for analysis of grain yield data collected from the experiments. AMMI analysis of variance for grain yield revealed significant effects (p < 0.01) for genotype, environment, and GE interaction. The environment was the main source of variation and accounted for 83.5% of the total yield variation, followed by GE (6.5%) and genotype (1.0%) effects. The AMMI biplot analysis indicated the genotypes G3, G23, G22, G10, and G19 as high yielding with stability performance across environments. Genotypes G14, G13, G20, and G9 showed large positive interaction with the environments featuring the highest rainfall during growing season, while genotypes G7, G6, and G21 had a large positive interaction with environments with low rainfall. Spearman’s rank correlation analysis revealed that the AMMI stability value, Shukla’s stability variance (σ2i), Wricke’s ecovalence (W2i), coefficient of determination (R2i), variance in regression deviations (S2di), and nonparametric statistic of S2(i) were not correlated with mean yield in tested genotypes, showing they are related to static/biological concept of stability. In contrast, the genotypic superiority index (Pi) and regression coefficient (bi) were significantly correlated (p < 0.01) with mean yield and corresponded to dynamic/agronomic concept of stability. These findings suggest that selection of genotypes should be considered based on selection objectives of using the various stability parameters described here. In conclusion, the selected genotypes in this study should be recommended as new cultivars or parental lines for grain yield and stability improvement under rainfed conditions of Iran or similar agro-ecologies.

Improving Grain Yield via Promotion of Kernel Weight in High Yielding Winter Wheat Genotypes.

Simple SummaryImproving plant net photosynthetic rates and accelerating water-soluble carbohydrate accumulation play an important role in increasing the carbon sources for wheat kernel growth and yield. The objective of this study was to quantify the relative yield contribution by analyzing the photosynthesis rate of flag leaf, water-soluble carbohydrate content of flag leaf, flag leaf sheath and stem, and other agronomic and physiological traits in 15 wheat cultivars released in Shandong Province, China between 1969 and 2006. Our results suggest that increase of flag leaf photosynthesis and WSC had a positive effect of 0.593 on the TKW, and thus benefit for developing high yielding wheat cultivars.Improving plant net photosynthetic rates and accelerating water-soluble carbohydrate accumulation play an important role in increasing the carbon sources for yield formation of wheat (Triticum aestivum L.). Understanding and quantify the contribution of these traits to grain yield can provide a pathway towards increasing the yield potential of wheat. The objective of this study was to identify kernel weight gap for improving grain yield in 15 winter wheat genotypes grown in Shandong Province, China. A cluster analysis was conducted to classify the 15 wheat genotypes into high yielding (HY) and low yielding (LY) groups based on their performance in grain yield, harvest index, photosynthetic rate, kernels per square meter, and spikes per square meter from two years of field testing. While the grain yield was significantly higher in the HY group, its thousand kernel weight (TKW) was 8.8% lower than that of the LY group (p < 0.05). A structural equation model revealed that 83% of the total variation in grain yield for the HY group could be mainly explained by TKW, the flag leaf photosynthesis rate at the grain filling stage (Pn75), and flag leaf water-soluble carbohydrate content (WSC) at grain filling stage. Their effect values on yield were 0.579, 0.759, and 0.444, respectively. Our results suggest that increase of flag leaf photosynthesis and WSC could improve the TKW, and thus benefit for developing high yielding wheat cultivars.

Evaluation of vegetable pigeonpea [Cajanus cajan (L.) Millsp] genotypes for yield stability

BackgroundVegetable pigeonpea is an important food security crop in the marginal dry areas of the Eastern region of Kenya. The adaptation and stability of vegetable pigeonpea genotypes across different agro-ecological zones in Kenya are not adequately determined. The objective of this study was to evaluate the yield stability and adaptability of genotypes: KAT 60/8, MZ 2/9, ICEAP 00554, ICEAP 00557 and KIONZA based on additive main effects and multiplicative interactions (AMMI) and Genotype plus genotype by environment (GGE biplot) analysis.MethodsEvaluation of vegetable pigeonpea Genotypes was conducted at Kiboko, Katumani and Kambi ya Mawe research stations located in Eastern region and University of Nairobi Field station in central region of Kenya. The genotypes were planted in a Randomized Complete Block design (RCBD), replicated three times at all sites. Rainfall at Kiboko and Kabete were supplemented with irrigation, using sprinklers, for a total of 38 times, providing 832 mm of water. The crop was protected from pests by the application of broad-spectrum, non-systemic, pyrethroid alpha-cypermethrin and dimethoate, after field scouting. All other agronomic and cultural practices were done as recommended for each location.ResultsCombined analysis of variance (ANOVA) at six environments revealed highly significant (P < 0.01) variations in G × E interactions for yield (Kg/ha), 100 Seed mass (g/100 seed), days to flower and maturity (P < 0.05). AMMI model for grain yield interaction principal components analysis (IPCA), explained 96.5% of the total yield variation. The cultivar MZ 2/9 and KAT 60/8 recorded a lower IPCA1, indicating a wider adaptation and stability. Kambi ya Mawe, Katumani and Kiboko had higher IPCA1, indicating greatest interactive environments and adapted genotypes. Kambi ya Mawe, was the most ideal location for evaluating pigeonpea genotypes. While KIONZA was the most ideal genotype for yield performance, MZ 2/9 and KAT 60/8 were most stable with a wider adaptation.ConclusionKIONZA should be used as a reference genotype, while Kambi ya Mawe would be the most ideal location for testing the vegetable pigeonpea genotypes in breeding research. Increased deployment of stable pigeon pea cultivars, MZ 2/9 and KAT 60/8 would enhance food security in the dry areas of Eastern regions of Kenya. These genotypes need to be promoted with farmers for wider adoption in the Eastern region of Kenya.

Phenotypic evaluation of genetic variability and selection of yield contributing traits in chickpea recombinant inbred line population under high temperature stress.

The online version contains supplementary material available at 10.1007/s12298-021-00977-5.

Performance of Rainfed Bread and Durum Wheat Cultivars Under Different Tillage Options in Wheat-Based Dryland Cropping Systems

The expansion of conservation agriculture (CA) requires an immediate attention on targeted breeding for the next generation of wheat cultivars that are adapted to CA system and maintain their productivity under severe drought conditions in unpredictable Mediterranean environments. In this study, eight released bread and durum wheat cultivars, differing in growth habit, were evaluated for grain yield and 15 agro-physiological traits under both conventional tillage (CT) and conservation agriculture (CA) systems using split-plot arrangements in randomized complete blocks design with three replications, in three cropping seasons (2017–2020) under rainfed conditions, at Sararood field station, Kermanshah, Iran. Cultivar, year and tillage-system main effects were significant (P < 0.01) and accounted for 1.5%, 57.8%, and 10.5% of the total variation in grain yield, respectively. The wheat cultivars performed better in conventional than conservation agriculture system with grain yield superiority varied from 4 to 35%, depending on amount and distribution pattern of precipitation over crop seasons. The best performing cultivar in conservation agriculture system was cv. Baran, winter bread wheat, while the best performing cultivar under conventional tillage was cv. Rijaw, facultative bread wheat. Cv. Sadra had the highest grain yield stability followed closely by cv. Rijaw. The positive relationships observed between grain yield and important agro-physiological traits, suggesting the efficiency of indirect selection of traits for improving grain yield under the two different tillage systems. The trait profile of wheat cultivars was strongly affected by year, depending on growth habit, and varied from one system to another. In conclusion, positive interaction of genotype and traits under two systems indicated that some traits (i.e., number of spike/m−2, SPAD reading, normalized difference vegetative index (NDVI), days to heading, 1000-kernel weight and grain filling duration) were effective in genotype adaptation to a particular system. Based on the findings, the distribution pattern of precipitation during cropping season was among the major determinant factor in success of rainfed wheat productivity. The wheat genotypes also significantly interacted with different tillage systems, implying the need for specific adaptation to tillage systems and environments.

Evaluation of genotype × environment interaction for grain yield of promising genotypes of rice (Oryza sativa L.) derived from mutation induction using the GGE-biplot method

The existence of genotype × environment interaction complicates the evaluation of cultivar performance and reduces gain to selection. One of the multivariate methods for interpreting genotype by environment interaction is GGE-Biplot, in which the main effect of genotype and genotype by environment interaction are investigated simultaneously. In this study, 13 mutant genotypes of rice along with three check cultivars Tarrom-Mahalli, Tarrom-Jelodar and Neda were evaluated for grain yield stability in the two locations of Sari and Tonekabon during the years 2016 and 2017 using randomized complete block design with three replications within each environment. The results of GGE-biplot analysis showed that the two first components explained 92.52% of the total yield variation. According to the polygon view, all four environments of the experiment were located in the place that the Neda cultivar was at the top. Genotypes 33, 30, 26, 31 were highly stable genotypes and genotypes 18, 16 and 25 were highly unstable. In this study, we found only one mega-environment. Also following Neda and Jelodar cultivars, genotype 31 was closest to the ideal genotype. Ton 95 was the most desirable environment.

ADAPTIVE PERFORMANCE OF GARLIC VARIETIES UNDER HIGH GANGES RIVER FLOODPLAIN SOIL (CALCAREOUS) OF BANGLADESH

Any variety needs to evaluate at different locations, along with variable soils for asses their yield potentiality after its releasing. Thus, an experiment was conducted at Multi Location Testing (MLT) site, Kushtia Sadar Upazila, under High Ganges River Floodplain (AEZ-11) in Bangladesh, during three consecutive Rabi seasons of 2013-2014 to 2015-2016. The objective of this study was to evaluate the performances of garlic varieties and economic profitability of these varieties at farmer’s field. There were three garlic varieties, namely BARI Rashun-1, BARI Rashun-2 and a local cultivar, which were evaluated at six dispersed locations as replications. Results observed that the highest yield (8.34-9.80 t ha-1) was obtained from BARI Rashun-1, which was followed by BARI Rashun-2 (7.43-9.48 t ha-1) and the local one (7.12-9.15 t ha-1). BARI Rashun-1 produced 3-12% higher yield over BARI Rashun-2 and 7-20% over the local cultivar, respectively in three consecutive years. Correlation analysis showed that there were positive and significant correlation among bulb yields with bulb length and individual bulb weight. Regarding the functional relationship, the traits like crop duration, plant population, plant height, bulb length, bulb width, individual bulb weight had positive contribution on the bulb yield. It was dependent on those traits, and accounted for 12, 36, 0.05, 45, 41 and 55% of the total bulb yield variation, respectively. The highest gross return (Tk. 3, 63,700 ha-1) and gross margin (Tk. 2,19,425 ha-1) were obtained from BARI Rashun-1. As such, this variety performed as the best, in respect of higher bulb yield potential, as well as the highest economic return among the tested varieties, which was followed by BARI Rashun-2. Therefore, the result of this study could be helpful for improving bulb production of garlic under High Ganges River Floodplain soil (calcareous soils) in Bangladesh.

Exploring long-term variety performance trials to improve environment-specific genotype × management recommendations: A case-study for winter wheat

• We used long-term wheat variety performance trials to evaluate G, E, and M effects. • Sub-region accounted for 46 % of the yield variability across all environments. • Management practices accounted for 44–77 % of yield variability within sub-regions. • Yield variability of 1–8 % was due to genotype within sub-regions. • Management practices and genotype traits improving yield varied by sub-region. The complex and interactive effects of genotype (G), environment (E), and management (M) can be a barrier to the development of sound agronomic recommendations. We hypothesize that long-term variety performance trials (VPT) can be used to understand these effects and improve regional recommendations. Our objective was to explore long-term VPT data to improve management and variety-selection recommendations using winter wheat ( Triticum aestivum L.) in the U.S. central Great Plains as a case-study. Data of grain yield, variety, and trial management were collected from 748 wheat VPT conducted in the states of Colorado, Kansas, and Oklahoma over nineteen harvest years (2000–2018) and 92 locations, resulting in 97,996 yield observations. Using 30-yr cumulative annual precipitation and growing degrees days, we partitioned the study region into 11 contiguous sub-regions, which we refer to as growing adaptation regions (GAR). We used variance component analysis, gradient boosted trees, and conditional inference trees to explore the management and variety trait effects within each GAR. For the variety trait analysis, the VPT dataset was reduced to account for varieties for which 17 agronomic traits and 11 disease/insect reaction ratings were available (65,264 yield observations). GAR accounted for 46 % of the total variation in grain yield, M for 32 %, residuals (including interactions) for 13 %, year for 7 %, and G for 2 %. Conditional inference trees identified interactions among management practices and their effects on yield within each GAR. For instance, water regime was the most important practice influencing wheat yield in the semi-arid western portion of the study region, followed by sowing date and fungicide. In dryland trials, there was typically an interaction between fungicide, sowing date, and tillage system, depending on GAR. Other management practices (e.g. dual-purpose management, crop rotation, and tillage practice) also significantly affected yield, depending on GAR. The main variety trait associated with increased yields depended on region and management combination. For instance, drought tolerance was the most important trait in dryland trials while stripe rust tolerance was more relevant in irrigated trials in the semi-arid region. In this research, we demonstrated an approach that uses widely available long-term VPT data to improve management and variety selection recommendations and can be used in other regions and crops for which long-term VPT data are available.

Selection of ideotype to increase yield potential of GM and non-GM rice cultivars

Using classical breeding, plant breeders envision a plant type whose yield they aim to enhance by selecting for individual traits to create model/ideal plants or ideotypes. To achieve this, those factors restricting yield need to be identified and controlled through the use of new technologies to achieve the desired ideotype. This study aimed to determine the ideotype of seven genetically modified (GM) and non-GM rice (Oryza sativa L.) cultivars. Field experiments were carried out in three isolated regions in the north of Iran under the Iranian bio-safety standard protocol. Four of the GM cultivars carried the cry1Ab gene in the vegetative stage while three non-GM cultivars served as the control. R2 values showed that five, six and seven variables in Sari, Amol and Rasht regions accounted for 63 %, 52 % and 74 % of paddy yield variation, respectively. In the same three regions, paddy yield variation due to white heads accounted for 28.38 %, 8.45 % and 3.95 % of the total variation in paddy yield, respectively. The total estimated variation in paddy yield in Sari, Amol and Rasht was 1810.50, 2377.6 and 2176.47 kg ha−1, respectively. Average data over the three regions indicated that highest loss in paddy yield was observed in non-GM ‘Nemat’, ‘Khazar’ and ‘Tarom Hashemi’. GM cultivars derived from ‘Khazar’ showed significantly lower paddy yield loss than the non-GM parent. Dead heart, a condition that occurs in the vegetative stage in which the stem borer larva enters the stem and feeds on the growing shoot, causing the central shoot to dry, as well as white heads, which is a condition in which whole ear heads of adult plants become dry and yield chaffy grains, in all three regions were important variables contributing to paddy yield loss. In the future, producing GM rice resistant to striped stem borer with an active promoter in the reproductive growth stage might allow farmers to reduce a significant part of paddy yield loss resulting from white heads, which is directly negatively correlated with filled spikelets per panicle (R2 = -0.57**), in order to achieve an ideotype.

Genotype and genotype × environment interaction effects on the grain yield performance of cowpea genotypes in dryland farming system in South Africa

The identification of stable and adaptable high yielding cowpeas (Vigna unguiculata (L.) Walp.) and highly discriminative environments will be useful for elite cultivar development in South Africa. Two statistical models, the Additive main effects multiplicative interaction (AMMI) and the genotype, genotype by environment biplot analysis have been used extensively to identify superior genotypes and ideal testing environments. Hence, the objective of this study was to identify elite cowpea lines and testing environments using the two models to inform future cultivar development strategies. Fifteen cowpea genotypes were evaluated for yield performance and stability across 3 different locations during 2016 and 2017 growing seasons in South Africa. Genotype main effects were significant for grain yield, while genotype × environment interaction effect was insignificant for grain yield. However, genotypic perfomance for grain yield was significantly affected by seasonal variability. The AMMI analysis of variance showed that genotypes (G), environments (E) and their interaction were significant for grain yield. The G and GE effects accounted for about 10% of the total variation in grain yield, while the environment accounted for 66%. The high yielding genotypes, Vigna Onb, TVU-5431 and Kisumu mix, were adapted to Mafikeng and Potchefstroom sites. Kisumu mix, followed by Vigna Onb, were the most stable genotypes, while Veg cowpea 1, Veg cowpea dacama cream and Veg cowpea 2 were the least stable genotypes across the three sites and seasons. The analysis also showed that Environment 4 (Potchefstroom) was the most ideal site for cowpea production among the test sites.

On Station Evaluation of Integrated Agriculture Aquaculture (IAA) on Yield of Potato (Solanum Tuberosum) and Tomato (Lycopersiconesculentum).

Evaluation of integrated agriculture aquaculture (IAA) was conducted on station in the National Fisheries and Aquatic Life Research center (NFALRC), Sebeta. In this trial the effect of irrigation with pond water and spring water and application of inorganic fertilizer on yield and other parameters for Tomato (Lycopersiconesculentum) and potato (Solanum tuberosum) were evaluated using randomized complete block design with three replications. Results show that there is variation in total yield and marketable yield as well as clusters per plant of tomato with plots treated with fertilizer having higher values. Among examined parameters, only clusters per plant of tomato varied significantly (P&lt;0.05) among treatments. However, marketable yield and yield per plant did not show significant variation (p&gt;0.05) among treatments. Nevertheless, all parameters in this trial did not show significant difference among treatments (P&gt;0.05). The results of this trial indicate that using pond water to irrigate horticulture plots can partially replace the use of inorganic fertilizers thereby reducing both cost and environmental effects.

Primary-tiller panicle number is critical to achieving high grain yields in machine-transplanted hybrid rice

The development of machine-transplanted hybrid rice is a feasible approach to meet the needs of both high grain yield and high labor efficiency in China, but limited information is available on the critical plant traits associated with high grain yields in machine-transplanted hybrid rice. This study was carried out to identify which type of culms (i.e., main stems and primary and secondary tillers) and which yield components of this culm are critical to achieving high grain yields in machine-transplanted hybrid rice. Field experiments were conducted with two hybrid rice cultivars grown under two densities of machine transplanting in two years. Results showed that total grain yield of main stems and primary and secondary tillers was not significantly affected by cultivar but was significantly affected by density and year. Averaged across cultivars, densities, and years, main stems and primary and secondary tillers contributed about 15%, 50%, and 35% to total grain yield, respectively. Total grain yield was not significantly related to grain yields of main stems and secondary tillers but was positively and significantly related to grain yield of primary tillers. Approximately 85% of the variation in total grain yield was explained by grain yield of primary tillers, which was positively and significantly related to primary-tiller panicles per m2 but not to spikelets per panicle, spikelet filling percentage, or grain weight of primary tillers. Based on these results, it is concluded that primary-tiller panicle number is essential for achieving high grain yields in machine-transplanted hybrid rice.

Evaluation of genotype × environment relationship in silage maize genotypes using biplot analysis and stability index

This study was conducted to evaluate the adaptability and stability of silage maize hybrids determing herbage and dry matter yield using Biplot analysis and some stability indexes. The studies were carried out using five registered corn varieties under irrigated conditions for six years (2013-2018) in Çarşamba plain of Samsun province, Turkey. The experimental layout was a Randomized Complete Block Design with four replications. Finlay and Wilkenson's regression and Eberhart and Russel's deviation from regression (S2d) coefficients were used in statistical analysis. Genotype (G) x environment (E) interactions were studied using the additive main effects and multiplicative interaction (AMMI) and G + GE (GGE) biplot models. The combined analysis of variance revealed significant (P&lt;0.01) effects of G, E and G × E interaction on herbage and dry matter yields. The analysis of variance indicated that 62.70% of variation in the herbage yield explained by E, 29.79% by the differences in G and 7.49% by the GE interaction. The analysis of variance indicated that 62.80% of the total variation in the dry matter yield accounted for E, 30.20% of the total variation by G and G × E interaction explained only 7.00% of the total variation in the data. The results of AMMI and GGE biplot models and stability analyses (R2, bi and S2di) revealed that PR31Y43 and Burak hybrids were stable in both herbage yield and dry matter yield.

Multi-Environment Evaluation and Genotype &amp;#215; Environment Interaction Analysis of Sorghum [&amp;lt;i&amp;gt;Sorghum bicolor&amp;lt;/i&amp;gt; (L.) Moench] Genotypes in Highland Areas of Ethiopia

Sorghum [Sorghum bicolor (L.) Moench] is a high-yielding, nutrient-use efficient, and drought tolerant crop that can be cultivated on over 80 per cent of the world’s agricultural land. However, a number of biotic and abiotic factors are limiting grain yield increase. Diseases (leaf and grain) are considered as one of the major biotic factors hindering sorghum productivity in the highland and intermediate altitude sorghum growing areas of Ethiopia. In addition, the yield performance of crop varieties is highly influenced by genotype × environment (G × E) interaction which is the major focus of researchers while generating improved varieties. In Ethiopia, high yielding and stable varieties that withstand biotic stress in the highland areas are limited. In line with this, the yield performance of 21 sorghum genotypes and one standard check were evaluated across 14 environments with the objectives of estimating magnitude G × E interaction for grain yield and to identify high yielder and stable genotypes across environments. The experiment was laid out using Randomized Complete Block Design with three replications in all environments. The combined analysis of variance across environments revealed highly significant differences among environments, genotypes and G × E interactions of grain yield suggesting further analysis of the G × E interaction. The results of the combined AMMI analysis of variance indicated that the total variation in grain yield was attributed to environments effects 71.21%, genotypes effects 4.52% and G × E interactions effects 24.27% indicating the major sources of variation. Genotypes 2006AN7010 and 2006AN7011 were high yielder and they were stable across environments and one variety has been released for commercial production and can be used as parental lines for genetic improvement in the sorghum improvement program. In general, this research study revealed the importance of evaluating sorghum genotypes for their yield and stability across diverse highland areas of Ethiopia before releasing for commercial production.

Multi-environment evaluation of foxtail millet advanced lines for forage yield stability

Foxtail millet (Setaria italica L. P. Beauv.) is a very important crop in the arid and semi-arid areas. In the present study, five advanced lines and one commercial check (Bastan) were tested across12 (six locations and two years) environments. An attempt was made to identify superior line(s) with emphasis on high forage yield potential and yield stability over multi-environment trials using GGE biplot analysis. The study was conducted using a randomized complete block design with four replications. Combined analysis of variance for forage yield showed that the genotypes, environments, and the interaction effects were highly significant (P ? 0.01). The environment, genotype and interaction effects accounted for 76.38%, 6.97% and 8.92% of the total forage yield variation, respectively. GGE biplot analysis showed that G5 has both high forage yield and stability across the studied environments and E3 and E4 were high-yielding environments in this study. Which-won-where study partitioned the testing locations into two mega-environments with G5 and G3 as winning genotypes in the first and second mega-environment, respectively. According to discriminate ability and representativeness, the E4 and E12 environments were perfect environments. Overall, existence of extensive crossover interaction clearly suggested that efforts are necessary to identify location-specific genotypes over multi-environment trials for release of new varieties.

Genetic and Phenotypic Parameters and Trends for Milk Yield, Service Period and Calving Interval and The Economic Impact of Extending A Calving Interval on-Farm Profitability in Friesian Cows in Egypt

Genetic parameters for Friesian cows were estimated from 9155 lactation records for 3635 cows sired by 184 bulls covered 34 years (1982-2015) in two herds Sakha and El-Karada , belonging to the Animal Production Research Institute, Ministry of Agriculture and Land Reclamation, Egypt. Multi-trait repeated animal models were employed using the REML procedure to estimate covariance components of total milk yield (TMY), service period (SP) and calving interval (CI). There is sufficient genetic variation (indicated by the coefficient of genetic variation) in total milk yield, service period and calving interval traits (15.6, 3.6 and 3.7%, respectively). Estimates of heritability for TMY, SP and CI traits were 0.170, 0.010 and 0.044, respectively. Permanent environmental variance ratios were 0.162, 0.017 and 0.048 for TMY, SP, and CI, respectively. Genetic correlations among SP and CI traits were high (0.998), however genetic correlations of reproductive with productive traits were unfavorable (0.512-0.661). The results indicated the possibility of continued selection for increased milk production which has deleterious effects on reproductive traits. The annual genetic changes were positive for TMY, SP, and CI (7.76 kg/yr, 0.076, and 0.24 d/yr, respectively). These positive trends indicate that there has been success in choosing better sires.The corresponding annual phenotypic changes for the same traits were positive (13.9 kg/yr, 0.029 and 0.82 d/yr, respectively). Positive annual genetic and phenotypic changes for SP and CI indicated that with improving milk yield the SP and CI will be increased. The financial situation of the farm is affected by the extension of the calving interval. The lower the calving interval, the more profitable the farm becomes, and prolonging this period for one day causes a financial loss for the farm.

Genotype and environment interaction of sweetpotato varieties

The article presents results of additive main effect and multiplicative interaction (AMMI) and genotype (G) main effect and genotype by environment (GE) interaction (G × GE) biplot analysis of a multi environmental trial (MET) data of 15 sweetpotato varieties released from Bangladesh Agricultural Research Institute conducted during 2015–2018. The objective of this study was to determine the effects of genotype, environment and their interaction on tuber yield and to identify stable sweetpotato genotypes over the years. The experimental layout was a randomized complete block design with three replications at Gazipur location. Combined analysis of variance (ANOVA) indicated that the main effects due to genotypes, environments and genotype by environment interaction were highly significant. The contribution of genotypes, environments and genotype by environment interaction to the total variation in tuber yield was about 60.16, 10.72 and 12.82%, respectively. The first two principal components obtained by singular value decomposition of the centred data of yield accounted for 100% of the total variability caused by G × GE. Out of these variations, PC1 and PC2 accounted for 71.5% and 28.5% of variability, respectively. The study results identified BARI Mistialu- 5, BARI Mistialu- 14 and BARI Mistialu- 15 as the closest to the “ideal” genotype in terms of yield potential and stability. Varieties ‘BARI Mistialu- 8, BARI Mistialu- 11 and BARI Mistialu- 12’ were also selected as superior genotypes. BARI Mistialu- 3 and BARI Mistialu- 13 was comparatively low yielder but was stable over the environment. Among them BARI Mistialu-12, BARI Mistialu-14 and BARI Mistialu-15 are rich in nutrient content while BARI Mistialu-8 and BARI Mistialu-11 are the best with dry matter content and organoleptic taste. Environments representing in 1st and 3rd year with comparatively short vectors had a low discriminating power and environment in 2nd year was characterized by a high discriminating power.&#x0D; Bangladesh J. Agril. Res. 44(3): 501-512, September 2019

Documenting production process and the ranking factors causing yield gap in rice fields in Sari, Iran

The documentation process is very important for identifying yield constraint factors and yield gap. For this purpose, all managing practices were recorded by monitoring of paddy rice fields in Sari region, Iran from 2015 to 2016. Field identifications were undertaken in such a way that they included all the main production procedures with variations in management viewpoints. The results revealed that seed consumption varied from 40 to 95 kg ha-1 and the range of seedling age varied from 20 to 50 days. Planting density was 10 to 66 plants per m2. Nitrogen application by 30% of the farmers ranged from 46 to 83 kg ha-1, and 40% of the farmers applied 83 to 138 kg of nitrogen per hectare. In 73% of the fields, nitrogen was not used after flowering stage. The range of yield varied from 3100 to 5430 kg ha-1, and in 60% of the studied fields, the paddy yield varied from 4205 to 5200 kg ha-1. In the comparative performance analysis (CPA) model, the actual yield and the yield potential were estimated to be 4495 and 6337 kg ha-1, respectively, and the yield gap was 1841 kg ha-1. Among the five variables entered in the model, the effects of potassium application and biological fight were remarkable, which the paddy yield increase by these variables was 709 and 806 kg ha-1, respectively, and equal to 39% and 44% of the total yield variation. Therefore, since the calculated potential yield was achieved through actual data in each paddy field, it seems this yield potential is attainable.

Effect of fertilizer application based on soil test crop response approach on active and passive pools of soil organic matter in maize–wheat cropping system

ABSTRACTA long-term fertilizer experiment was initiated in kharif 2007 in a maize–wheat sequence at the Experimental Farm of Department of Soil Science, Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya, Palampur under the network of All India Coordinated Research Project on Soil Test Crop Response (STCR) Correlation Studies. The experiment consisted of eight treatments (control, general recommended dose, soil test based, farmers’ practice, target yield of 25 (rabi)/30 (kharif) and 35 (rabi)/40 (kharif) q ha−1 either with or without 5 t ha−1 farm yard manure) replicated thrice in a randomized block design. All the passive and active pools of soil organic matter (SOM) were highest under STCR treatments for target yield 35 q ha−1 + farmyard manure (FYM). The highest value of both humic and fulvic acids under STCR treatment for target yield 35 q ha−1 with FYM was statistically at par with treatment for target yield 25 q ha−1 with FYM. The R2 value indicated that about 96% to 98% of the total variation in grain yield was attributable to SOM fractions. The contribution of all fractions of SOM towards the total variation in straw yield was 96% to 97%.