Grain Yield Of Cultivars Research Articles

Effect of VRN1 and PPD1 genes on anthesis date and wheat growth

Phasic development of wheat is largely determined by the interaction of the VRN1 and PPD1 genes with vernalising temperature and photoperiod. VRN1 and PPD1 are regulatory genes, known to influence freezing tolerance, plant morphology and grain yield as well as phasic development. Forty-seven doubled-haploid lines were characterised for Ppd-B1, Ppd-D1, Vrn-A1, Vrn-B1 and Vrn-D1 to determine the effect of allelic combinations of these genes on timing of anthesis and crop growth rate. The lines were grown in replicated field experiments at two locations in Australia. The VRN1 and PPD1 genes accounted for 75% of the genetic variation for time from sowing to anthesis. Vrn-A1 and Vrn-B1 similarly affected time to anthesis, but only Vrn-B1 affected crop growth rate, with the spring Vrn-B1a allele resulting in faster crop growth rates than the winter Vrn-B1v allele. This suggests that the effect of Vrn-B1 on crop growth rate is not a direct consequence of its effect on development per se, but rather due to its influence on other physiological processes. The faster growth associated with Vrn-B1a may explain the high grain yield of cultivars with this allele in some environments, as shown in a previous study.

Adaptability and stability of soybean cultivars for grain yield and seed quality.

This study aimed at verifying the adaptability and stability of soybean cultivars, considering the grain yield and quality of seeds, adopting univariate and multivariate approaches. The experiments were conducted in two crops, three environments, in 2013/2014 and 2014/2015 crop seasons, in the county of Inconfidentes, Lavras, and Patos de Minas, in the Minas Gerais State, Brazil. We evaluated 17 commercial soybean cultivars. For adaptability and stability evaluations, the Graphic and GGE biplot methods were employed. Previously, a selection index was estimated based on the sum of the standardized variables (Z index). The data relative to grain yield, mass of one thousand grain, uniformity test (sieve retention), and germination test were standardized (Zij) per cultivar. With the sum of Zij, we obtained the selection index for the four traits evaluated together. In the Graphic method evaluation, cultivars NA 7200 RR and CD 2737 RR presented the highest values for selection index Z. By the GGE biplot method, we verified that cultivar NA 7200 RR presented greater stability in both univariate evaluations, for grain yield, and for selection index Z.

Genetic Improvement of Extra‐Early Maize Cultivars for Grain Yield and Striga Resistance during Three Breeding Eras

Maize (Zea mays L.), a food security crop in West Africa (WA) is threatened by Striga hermonthica (Del.) Benth. infestation. A study was conducted at five locations in WA for 2 yr to determine genetic gains in grain yield of 56 extra‐early maturing cultivars developed during three breeding eras, 1995 to 2000 (Era 1), 2001 to 2006 (Era 2), and 2007 to 2012 (Era 3) under Striga‐infested and Striga‐free conditions. Yield ranged from 1827 kg ha−1 for Era 1 cultivars to 2292 kg ha−1 for Era 3 cultivars under Striga infestation with average rate of increase in grain yield of 42 kg ha−1 yr−1 corresponding to 2.56% annual genetic gain. Under Striga‐free conditions, yield ranged from 2939 kg ha−1 for Era 1 cultivars to 3549 kg ha−1 for Era 3 cultivars, but the average rate of increase in grain yield of 54 kg ha−1 yr −1 corresponding to 1.3% annual genetic gain was not significant. The increase in yield under Striga was associated with increased plant height. Although there was no significant gain in yield under Striga‐free conditions, significant increase in plant height and decrease in root lodging were observed. Cultivars 53, 17, and 45 from Era 3 and 23, 21, 34, and 28 from Era 2 were the highest yielding and most stable under Striga infestation. Cultivars 53 and 55 from Era 3 were the most outstanding under Striga‐free conditions. Considerable progress has been made in breeding for high yielding and Striga resistant or tolerant extra‐early maize cultivars during the last three decades.

Adaptability and phenotypic stability of soybean cultivars for grain yield and oil content.

The aim of this study was to verify the adaptability and stability of soybean cultivars with regards to yield and oil content. Data of soybean yield and oil content were used from experiments set up in six environments in the 2011/12 and 2012/13 crop seasons in the municipalities of Patos de Minas, Uberaba, Lavras, and São Gotardo, Minas Gerais, Brazil, testing 36 commercial soybean cultivars of both conventional and transgenic varieties. The Wricke method and GGE biplot analysis were used to evaluate adaptability and stability of these cultivars. Large variations were observed in grain yield in relation to the different environments studied, showing that these materials are adaptable. The cultivars exhibited significant differences in oil content. The cultivars BRSGO204 (Goiânia) and BRSMG (Garantia) exhibited the greatest average grain yield in the different environments studied, and the cultivar BRSMG 760 SRR had the greatest oil content among the cultivars evaluated. Ecovalence was adopted to identify the most stable cultivars, and the estimates were nearly uniform both for grain yield and oil content, showing a variation of 0.07 and 0.01%, respectively. The GGE biplot was efficient at identifying cultivars with high adaptability and phenotype stability.

Physiological and biochemical responses of wheat cultivars (<italic>Triticum aestivum</italic> L.) to cold stress conditions

Field and laboratory experiments were carried out to determine the effect of cold stress on fifteen wheat (<italic>Triticum aestivum</italic> L.) cultivars. Fifteen cultivars including winter cultivars <italic>viz.</italic>, Sayson, Marton, Gaskoghen, C-82-12, C-82-13, facultative cultivars: Alvand, Mahdavi, Zarrin, Marvdasht, Tous and spring cultivars <italic>viz.</italic>, Shiraz, Pishtaz, M-79-7, M-81-13, Kavir were sown at three dates (15 October, 15 November and 15 December) based on complete blocks design with three replications under field conditions. In laboratory experiment the same cultivars were evaluated under cold stress at two and four leaves growth stages. Results showed that there were significant differences among cultivars in grain yield, potassium accumulation, lethal temperature (LT<sub>50</sub>), ion leakage, chlorophyll content a and b among growing stages, genotypes and interaction between them. Ion leakage was the highest for M-81-13 cultivar (81.12ds m<sup>-1</sup>). C-82-12 and Gaskogen with more than 6.44 % and Sayson with 4.89 % potassium accumulations had the highest and lowest values. Lethal temperature of Gaskogen and Shiraz were -42 and -28°C. Gaskogen was tolerant to cold stress and hadn't high grain yield potential. The highest chlorophyll a and proline content were obtained for Marvdasht and Gaskoghen with 2.51mg.g<sup>-1</sup> and 0.34μg.g<sup>-1</sup> at two leaves growth stage. In contrast the lowest chlorophyll b related to Sayson and C-82-12 with 1.37 and 1.39 mg g<sup>-1</sup>, respectively. All cultivars at first planting date had more grain yield than two other planting dates.

Consistency of performance of early-maturing maize cultivars in Striga-infested and Striga-free environments

Badu-Apraku, B., Yallou, C., Oyekunle, M., Akinwale, R., Aweke, G. and Kamara, A. 2015. Consistency of performance of early-maturing maize cultivars in Striga-infested and Striga-free environments. Can. J. Plant Sci. 95: 1073–1084. Despite the immense potential of maize (Zea mays L.) in savannas of West and Central Africa (WCA), production and productivity is constrained by Striga hermonthica parasitism. Sixteen early-maturing cultivars were evaluated at two locations in Nigeria and three locations in the Republic of Benin from 2007 to 2009 to assess the grain yield, stability and the consistency of the rankings of the cultivars under Striga-infested and Striga-free environments. The combined analysis of variance showed significant (P<0.01) cultivar and cultivar×environment interactions for grain yield and other traits under Striga-infested and Striga-free environments. The test of concordance was significant (P<0.001) for grain yield (W=0.68), number of emerged Striga plants (W=0.74) and Striga damage (W=0.56) under Striga infestation, indicating stability of resistance in the cultivars developed from diverse sources under artificial S. hermonthica infestation across environments. There was high consistency of the rankings of the cultivars for grain yield and other Striga-resistance traits under Striga-infested and Striga-free environments in Benin and Nigeria. The additive main effects and multiplicative interaction (AMMI) biplot analysis for grain yield revealed POOL15SR/ACR94TZECOMP5-W/ACR94TZECOMP5-W and 2004 TZE-Y Pop DT STR C4 as the most stable cultivars with above-average mean grain yield in Striga-infested environments and they can be combined with other crop management options to control the parasite in the Striga endemic environments. Cultivars TZE Comp 5-W C7F2 and TZE Comp5-Y C6 S6 (Set B) had less Striga damage and number of emerged Striga plants across test environments. These cultivars could therefore serve as unique sources of favorable alleles for improving Striga resistance in maize in different production environments and farming systems.

Examination of genotype × environment interactions by GGE biplot analysis in spring durum wheat

A study was conducted to examine the effects of genotype × environment interaction (GEI) on grain yield, its components, and quality characteristics using genotype main effect (G) plus genotype × environment interaction (GE) (GGE) biplot analysis. Significant differences were observed among cultivars in grain yield, yield components, and quality traits and the relationship between yield components was used to identify three groups. Positive correlations were found between quality parameters and yield components, whereas correlations of quality parameters with yield and yield components were negative. The GGE biplot indicated that E6 (single irrigated location at Diyarbakir) was an ideal environment for all traits and E5 (rainfed locations at Diyarbakir) was a highly efficient model for quality parameters. The biplot analysis showed that Zenit was the best cultivar in terms of yield and quality and Zuhre was efficient for quality parameters only and hence these two genotypes can be recommended to Southeastern Anatolia Region in Turkey.

Comparison of photoperiod-sensitive and photoperiod-insensitive basmati cultivars for grain yield, water productivity, and quality traits under varied transplanting dates in Northwest India

In order to increase yield and water productivity, arrest the mining of groundwater, and achieve quality production in Northwest India, there is a need to optimise the transplanting time for newly evolved, high-yielding basmati cultivars. This study in the Indian Punjab was aimed at investigating the effect of date of transplanting (5, 15, and 25 July) on yield, quality traits, and water productivity of four basmati rice cultivars (Pusa Basmati 1121, Pusa Basmati1509, Punjab Basmati 3, and Basmati 386) varying in photoperiod sensitivity. Water productivity of Pusa Basmati1509 was higher than of photoperiod-sensitive cultivars (Punjab Basmati 386 and Punjab Basmati 3) for each transplanting date. Water productivity [irrigation, WPI; total (irrigation + rainfall), WPI+R; and real crop, WPET] of Punjab Basmati 3 for the 25 July transplanting was similar to Pusa Basmati 1509 for the 5 July transplanting. For the 25 July transplanting, WPI, WPI+R, and WPET of Pusa Basmati 1509 increased by 48.9%, 35.2%, and 22.5%, respectively, relative to Pusa Basmati 1121; by 34%, 31.4%, and 27.5% relative to Punjab Basmati 3; and by 81.1%, 70.4%, and 56% relative to Basmati 386. The study showed that delaying transplanting of photoperiod-sensitive and short-duration, photoperiod-insensitive basmati cultivars helped to improve water productivity and quality traits, particularly the head rice recovery (%), kernel length after cooking, and amylose content.

Foliage applied boron improves the panicle fertility, yield and biofortification of fine grain aromatic rice

Boron (B) deficiency in rice field is becoming a common problem in South Asia. Correcting B deficiency in rice has potential to improve the rice productivity. Foliage application of B is an easy and effective way to resolve this problem. This study was conducted to evaluate the influence of foliage applied (0.16, 0.24, 0.32, 0.40 and 0.48 M) B on leaf elongation, tillering, water relations, yield and B grain enrichment of rice cultivars Super Basmati and Shaheen Basmati. Foliage applied B improved leaf elongation, tillering, leaf chlorophyll contents, water relations, grain yield, yield-related traits and B grain contents with simultaneous decrease in panicle sterility. However, foliage application of 0.32 M B was the most effective in this regard. An increase in leaf and grain B contents was observed with increase in B concentration in the foliar spray. There was no difference between the cultivars for grain yield; however, Shaheen Basmati had more grain weight, and grain and leaf B contents than Super Basmati. Boron foliage application (0.32 M B) proved an effective way to correct B deficiency in rice. Improvement in grain yield by B application was attributed to increase in grain size and decrease in panicle sterility.

Involvement of 1-Methylcyclopropene in Plant Growth, Ethylene Production, and Synthase Activity of Inferior Spikelets in Hybrid Rice Differing in Panicle Architectures

Chlorophyll content (SPAD values) of leaves, 1-aminocyclopropane-1-carboxylic acid synthase (ACS) activities and ethylene production of inferior spikelets, aboveground biomass, grain yield, and yield components were studied to compare the effects of 1-methylcyclopropene (1-MCP) on plant growth, and inferior spikelet development in hybrid rice (Oryza sativa L.) differing in panicle architectures. There were four hybrid rice cultivars in this trial, including two lax-panicled cultivars, Liangyoupeijiu (LYPJ) and Guodao 6 (GD6), and two compact-panicled cultivars, Yongyou 9 (YY9) and Yongyou 12 (YY12). Results showed that chlorophyll content of leaves in 1-MCP treatment was higher than control (CK) after application of 1-MCP. ACS activities and ethylene production in 1-MCP treatment for LYPJ, GD6, and YY9 were significantly decreased compared to their corresponding CK. Aboveground biomass and grain yield of cultivars were increased with the increase of chlorophyll content of leaves, but decreased with the increase of ACS activities and ethylene production of inferior spikelets. On average, grain yield in 1-MCP treatment for LYPJ was increased by 7.3 % compared to CK, GD6 was increased by 2.6 %, YY9 was increased by 3.2 %, and YY12 was increased by 0.8 %, respectively. Application of 1-MCP showed marked effects on increasing spikelet fertility and harvest index of cultivars, but exhibited little effects on improving sink capacity and 1,000-grain weight. Our results indicate that 1-MCP could play a positive role in regulating the growth and development of hybrid rice with lax panicles or with compact panicles.

Yield response of diallelic crossed maize (Zea mays L.) genotypes to varying nitrogen regimes in Nigeria

Context: Development of early maturing maize cultivars that remain productive under low N fertilizer farming system, consistent with the farmers’ technologies is a prerequisite to improving adoption of new varieties without increasing production cost. Objective: To assess the performance of ten early open pollination maize varieties (OPVs) and their F1 hybrids for grain yield and nitrogen use efficiency (NUE), and also identify productive cultivars under low N fertilizer regimes. Materials and Methods: The trials were set up in a split plot arrangement with three N fertilizer levels (0, 45 and 90 kg N ha-1) as main plot and the genotypes as sub-plot. Each plot within N level was four-row, laid out in a randomized complete block design of four replications. Ten OPVs were crossed in a half diallel to generate 45 F1 hybrids during 2004 and 2005 growing seasons. Planting were carried out on 20th July, 2005 and 2nd July, 2006. Agronomic characters studied were grain yield, maize establishment count, days to 50% tasselling and silking as well as plant and ear heights. Results: The year 2005 growing season was better for all observed characters amongst all the genotypes than the year 2006. Although, expressions of these traits in the hybrids were relatively higher than the OPVs including the grain yield. The total increase in grain yield observed was 1.72 t ha-1 and 1.95 t ha-1 for OPVs and hybrids respectively on application of 90 kg ha-1 over no N-application. However, NUE was optimum at 45 kg N ha-1 in both groups. Grain yield and NUE correlated positively with growth characters measured except for days to 50% silking. Higher genetic gains were recorded for plant and ear heights. Conclusion: Two drought tolerant varieties (Acr 90 Pool 16-Dt and Tze Comp3 Dt) that combined well with specific cultivars for grain yield and NUE probably have gene pools for low N-tolerance. DOI: http://dx.doi.org/10.3329/jbs.v19i0.13000 J. bio-sci. 19 43-52, 2011

Evaluation of some morphological traits associated with wheat yield under terminal drought stress

This study was carried out at the Seed and Plant Improvement Institute, Karaj (Iran) in 2007/2008 and 2008/2009 growing seasons to investigate the effects of two irrigation regimes (normal irrigation and no irrigation in post-anthesis growth stage) on grain yield of eight wheat cultivars (DM-81-6, DM-82-1, Bahar, DN-11, DN-7, Pishtaz, WS-82-9, and C-85-6). According to the results of variance analysis, it is clear that there is a significant difference among the testing cultivars in grain yield and yield components. It is a result of difference in grain yield reduction among genotypes under different irrigation regimes. DN-11 Genotype produced the highest grain yield under both irrigation regimes. The yield reduction of Bahar genotype was the highest under drought stress conditions. Based upon the result of stepwise regression analysis, the most important yield components were biological yield, harvest index, and 1000 grain yield. Key words:

Induction of drought tolerance with seed priming in wheat cultivars (Triticum aestivum L.)

Delay in sowing and low precipitation (<300mm annual) in wheat (Triticum aestivum L.) farming is the major problem in the irrigated and rainfall lands of Iran. A factorial experiment for evaluating the effects of seed priming on wheat cultivars was carried out under laboratory, greenhouse and at two field conditions during seasons of 2008-2010. Arrangement of treatments were Zarrin, Shariar, Sardary and Azar cultivars as A factor, and priming treatments including distilled water (DW), osmotic solutions (10% PEG, 2.5% KCl, 4% MN, 10% Urea, 5% NaCl W/V) and plant growth inducers (20 ppm IAA, 1000 ppm CCC) with non-primed seed as a control established B factor. During the second year of field experiment two separate treatments were done under drought stress and well watered conditions. Drought stress was withheld by irrigation at booting stage of plants. Maximum amount of absorbed water was determined in cultivar Shariar, 15.5 g DW. Seed weight of all cultivars increased the most when primed with CCC and IAA. Irrespective of the cultivar seedlings related traits revealed that treatment with CCC increased plumule and radical dry weights (11.5 and 8.0 mg) and their lengths (17.2 and 17.8 cm). In opposite, urea pretreatment had negative effects on seedlings growth. All priming treatments increased grain yield and its components, chlorophyll content and nitrogen absorbed under field and green house conditions in four cultivars in comparison to control. Plants arising from seeds primed with potassium chloride under drought stress had the lowest percentage of variation for traits such as relative water content (-9.3%), total dry matter (-10.7%) and grain yield (-4.0%) in comparison with well watered plants. Potassium chloride improved drought tolerance at all wheat cultivars. There were significant correlations between grain yield at primed with KCl and following wheat traits: number of spikes per square meter (0.91**), number of grains per spike (0.92**) and total dry matter (0.79*). Therefore, it seems that these traits could be used as indirect criteria for selection of high grain yield of cultivars for primed seed.

Induction of drought tolerance with seed priming in wheat cultivars (Triticum aestivum L.)

Delay in sowing and low precipitation (<300mm annual) in wheat (Triticum aestivum L.) farming is the major problem in the irrigated and rainfall lands of Iran. A factorial experiment for evaluating the effects of seed priming on wheat cultivars was carried out under laboratory, greenhouse and at two field conditions during seasons of 2008-2010. Arrangement of treatments were Zarrin, Shariar, Sardary and Azar cultivars as A factor, and priming treatments including distilled water (DW), osmotic solutions (10% PEG, 2.5% KCl, 4% MN, 10% Urea, 5% NaCl W/V) and plant growth inducers (20 ppm IAA, 1000 ppm CCC) with non-primed seed as a control established B factor. During the second year of field experiment two separate treatments were done under drought stress and well watered conditions. Drought stress was withheld by irrigation at booting stage of plants. Maximum amount of absorbed water was determined in cultivar Shariar, 15.5 g DW. Seed weight of all cultivars increased the most when primed with CCC and IAA. Irrespective of the cultivar seedlings related traits revealed that treatment with CCC increased plumule and radical dry weights (11.5 and 8.0 mg) and their lengths (17.2 and 17.8 cm). In opposite, urea pretreatment had negative effects on seedlings growth. All priming treatments increased grain yield and its components, chlorophyll content and nitrogen absorbed under field and green house conditions in four cultivars in comparison to control. Plants arising from seeds primed with potassium chloride under drought stress had the lowest percentage of variation for traits such as relative water content (-9.3%), total dry matter (-10.7%) and grain yield (-4.0%) in comparison with well watered plants. Potassium chloride improved drought tolerance at all wheat cultivars. There were significant correlations between grain yield at primed with KCl and following wheat traits: number of spikes per square meter (0.91**), number of grains per spike (0.92**) and total dry matter (0.79*). Therefore, it seems that these traits could be used as indirect criteria for selection of high grain yield of cultivars for primed seed.

Genetic Variation and Agronomic Evaluation of Chickpea Cultivars for Grain Yield and Its Components Under Irrigated and Rainfed Growing Conditions

Water deficit is an important factor limiting crop growth all over the world. In order to evaluate genetic variation, heritability and the interrelationship between agronomic traits, twenty chickpea genotypes were cultivated in two separated randomized complete block experiments with three replications under normal irrigated and rainfed conditions. The experiments were carried out at the Agricultural Research Station of Razi University, Kermanshah, Iran, in the 2004-2005 growing season. Under normal conditions, plants were irrigated at stem elongation, pod appearance and pod filling stages. In rainfed conditions, no irrigation treatment was applied. The results revealed that the genotypes S95274 under irrigated and X95TH69 in rainfed conditions had the highest number of pods per plants (NPP), number of seeds per plant (NSP) and grain yield. The genotypes X96TH54 and X95TH69 produced relatively high grain yield compared to other genotypes in both conditions. The highest genotypic and phenotypic coefficients of variation in irrigated (32.61% and 34.67%, respectively) and in rainfed conditions (47.88% and 49.39%, respectively) and also the highest estimation of heritability in both conditions (88% and 93%, respectively) belonged to grain yield. In rainfed growing conditions, the correlations between grain yield and its components were significantly positive while in irrigated conditions grain yield showed significant correlation with NPP (r=0.50) and NSP (r=0.49). According to the results of path analysis, the highest direct (0.99 and 0.73 in irrigated and rainfed conditions, respectively) and indirect effects (0.89 in irrigated and 0.71 in rainfed experiments) on grain yield belonged to NSP and NPP respectively. Based on cluster analysis method, genotypes were classified into three and four groups in irrigated and rainfed conditions, respectively. It can be concluded that the NPP and NSP traits could be used as selection criteria for grain yield improvement in both conditions in chickpea breeding programs.

Registration of ‘Merl’ Wheat

‘Merl’ (Reg. No. CV‐1052, PI 658598) soft red winter (SRW) wheat (Triticum aestivum L.), developed and tested as VA03W‐412 by the Virginia Agricultural Experiment Station, was released in March 2009. Merl was derived from the three‐way cross ‘Roane’/Pioneer variety 2643//‘38158’ (PI 619052). Merl is a broadly adapted, high‐yielding, mid‐season, moderately short, semidwarf (Rht2) cultivar having above‐average straw strength and milling and pastry‐baking qualities. Merl is resistant to powdery mildew [caused by Blumeria graminis (DC.) E.O. Speer] and moderately resistant to stripe rust (caused by Puccinia striiformis Westend.). In Virginia, Merl ranked among the top five cultivars for grain yield with a 3‐yr (2007–2009) average of 5725 kg ha−1 Merl had a mean grain volume weight of 76.4 kg hL−1 across 22 environments, which was significantly (P &lt; 0.05) higher (1.9–3.0 kg hL−1) than that of the other top‐yielding cultivars. In USDA‐ARS Uniform Eastern SRW Wheat Nursery trials conducted at 29 locations, Merl ranked sixth among 46 entries for grain yield (5917 kg ha−1) and seventh for grain volume weight (76.0 kg hL−1) in 2006 and ranked second among 45 entries for grain yield (5529 kg ha−1) and sixth for grain volume weight (75.7 kg hL−1) in 2008. Merl has a soft grain texture, flour softness equivalent values from 57.5 to 60.8 g 100 g−1, and straight‐grade flour yields from 70.5 to 71.5 g kg−1 The flour protein concentration (7.5–8.7 g 100 g−1) and gluten strength, assessed via lactic acid solvent retention capacity (101–104 g 100 g−1), of Merl are lower than average. These quality attributes contribute to Merl's above‐average pastry‐baking quality (cookie‐spread diameters of 17.93–18.93 cm).

Nutrient use efficiency and arbuscular mycorrhizal root colonisation of winter wheat cultivars in different farming systems of the DOK long-term trial

For organic farming, cultivars are required with high nutrient use efficiency under nutrient limited conditions. Arbuscular mycorrhizal fungi (AMF) are known to contribute to nutrient uptake under low input conditions. We compared nutrient use efficiency (NUE) of old and modern organically and conventionally bred cultivars in organic and conventional systems and assessed AMF-root colonisation (AMF-RC) in relation to nutrient concentrations. Cultivars and systems had a statistically significant effect on nitrogen (N) and phosphorus (P) concentrations and NUE parameters, whereas no genotype x environment interactions appeared. In contrast to N and P uptake, the NUE parameters were higher under organic than under conventional conditions. NUE for N increased with the year of release of cultivars. In the organic systems, the organically bred cultivars could not outperform the conventionally bred cultivars in grain yield and NUE parameters. AMF-RC was higher in the organic than in the conventional system, but did not differ among cultivars. Cultivars achieving high NUE in the organic systems were found among modern cultivars, irrespective of the breeding programme. Nutrient conditions during the breeding programme did not affect AMF-RC. No clear evidence was found that AMF symbiosis contributed more to nutrient concentrations under low input than under high input conditions.

English

Analysis of multienvironment trials (METs) of crops for cultivar evaluation and recommendation is an important issue in plant breeding research. Evaluating both stability of performance and high yield is essential in MET analyses. The objectives of this study were to assess interrelationship among these measures and to identify high-yield and stable barley (Hordeum vulgare&nbsp;L.) cultivars in 11 environments during 2001 - 2003 in the central Black Sea region of Turkey. Significant differences were observed among barley cultivars for grain yield, thousand-grain weight, hectoliter weight, plant height and heading date.&nbsp;In this study, high values of TOP (proportion of environments in which a genotype ranked in the top third) was associated with high mean yield,&nbsp;but the other methods were not positively correlated with mean yield and instead characterized a static concept of stability. The results of principal component (PC) analysis and correlation analysis of parametric and nonparametric stability statistics and yield indicated that only TOP method would be useful for simultaneously selecting for high yield and stability. This method recommended Fahrettinbey and Sladoran as stable and Balkan 96 and Erginel as unstable genotypes. A biplot of the first two PCs also revealed that the stability statistic methods grouped as three distinct classes that corresponded to different dynamic (agronomic) and static (biological) concepts of stability. &nbsp; Key words:&nbsp;Barley,&nbsp;genotype x environment interaction, parametric and nonparametric measures, dynamic and static stability.

Response of Upland Rice Cultivars to Nitrogen Fertilizer in the Savannas of Nigeria

In the dry savannas of West Africa, cultivation of upland rice (Oryza spp.) under rain‐fed conditions is expanding due to the introduction of the New Rice for Africa (NERICA; WARDA, Bouake, Cote d'Ivoire) but appropriate N recommendations for these new cultivars are lacking. The present study evaluated the response of four NERICA rice cultivars, their parents (WAB 56‐104 (O. sativa, tropical japonica type), CG 14 [O. glaberrima]) to four rates of N (0, 30, 60, and 90 kg ha−1) at Sabon‐Gari (Sudan savanna, SS) and Tilla (northern Guinea savanna, NGS) in 2007 and 2008. There was no interaction between N rates and rice cultivars for grain yield, suggesting that the rice cultivars responded similarly to N application. Grain yield of NERICA rice cultivars responded significantly to N application in the Nigerian dry savannas following a linear response, even at 90 kg N ha−1, thus optimum rate might be above this N level. NERICA 1, NERICA 3, and NERICA 4 had comparable yields and produced 1.4 to 1.7 times more grains than the other cultivars in Sabon‐Gari; while in Tilla, NERICA 4 and WAB56‐104 produced the highest yield. NERICA 1, NERICA 3, and NERICA 4 may be more suitable for cultivation in Sabon‐Gari (SS) while NERICA 4 and WAB56‐104 can be recommended for Tilla (NGS).

Grain yield, nutrient content and lipid profile of oat genotypes grown in a semiarid environment

The objective was to evaluate oat cultivars for grain yield and quality in two years of different climatic conditions. Cultivars were chosen for forage yield, pest resistance or environmental stress tolerance. The study, in 2004 and 2005, included 15 cultivars of Avena sativa and three of Avena byzantina seeded in 1.4 by 5.5 m plots. One set of plots was managed for dual purpose (DP), and a second set was only for grain (GO). Total grain yield (GYLD) and hectolitre weight (HW) was determined for DP and GO, while grain samples from DP were analyzed for crude protein (CP); ether extract (EE), starch (STA), β-glucan (β-GLU), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and fatty acid composition. Significant interactions of cultivars by year were found for all traits. Overall GYLD was 88% higher when oat was managed for GO. The highest yields within DP were for Bw 103, Canai, Pilar, Polaris, Rocío (2004) and U 16 (2005). For GO, cultivars Payé, Polaris and U 16 (2004) and Maja (2005), respectively showed the best yields. Overall and yearly means were numerically similar for HW within genotypes and management. Greater CP NDF, ADL, β-GLU variability was observed in 2004 compared with 2005. However ADF and STA did not appear to be influenced by year, with similar yearly means. For STA content, the most stable cultivars in both years were Milagros and Cristal, with STA values higher than 39%. For NDF and ADF concentration Tucana was the most stable cultivar. Cultivars Bw 103, Máxima and Rocío exhibited the highest β-GLU values in both years. The fatty acids palmitic, oleic and linoleic acids were 91% of total in both years with greater variability and mean content in 2004. Low to moderate but significant correlation coefficients were: STA with GYLD ( R = 0.45), NDF ( R = −0.41) and HW ( R = 0.38); GYLD with β-GLU ( R = 0.55) in 2004; and NDF with HW ( R = −0.41) in 2005. The relationship found for EE and fatty acids were less affected by year, and the more relevant associations were: EE and oleic ( R = 0.57), palmitic and estearic ( R = 0.54), estearic and linolenic ( R = 0.60) and oleic and linoleic ( R = −0.72). All variables seem more influenced by environment than by genotype.