Reduced Irrigation Conditions Research Articles

Biochar amendment modulates xylem ionic constituents and ABA signaling: its implications in enhancing water-use efficiency of maize (Zea mays L.) under reduced irrigation regimes

While biochar amendment is known to enhance plant productivity and water-use efficiency (WUE), particularly under water-limited conditions, the specific mechanisms driving these benefits remain largely elusive. Thus, the present study was conducted to elucidate the synergistic effects of biochar and reduced irrigation on maize (Zea mays L.) plants, focusing on xylem composition, root-to-shoot signaling, stomatal behavior, and WUE. Maize plants were cultivated in split-root pots filled with clay loam soil, amended by either wheat-straw (WSB) or softwood (SWB) biochar at 2% (w/w). Plants received full (FI), deficit (DI), or alternate partial root-zone drying (PRD) irrigation from the fourth leaf to the grain-filling stage. Our results revealed that WSB amendment significantly enhanced plant water status, biomass accumulation, and WUE under reduced irrigation, particularly when combined with PRD. Although reduced irrigation inhibited photosynthesis, it enhanced WUE by modulating stomatal morphology and conductance. Biochar amendment combined with reduced irrigation significantly increased xylem K+, Ca2+, Mg2+, NO3-, Cl-, PO43-, and SO42- while decreased Na+, which in turn lowered xylem pH. Moreover, biochar amendment and especially WSB amendment further resulted in increased abscisic acid (ABA) contents in both leaf and xylem sap under reduced irrigation conditions due to changes in xylem ionic constituents and pH. The synergistic interactions between xylem components and ABA led to refined adjustments in stomatal size and density, thereby affecting stomatal conductance and ultimately improving WUE of maize plants at different scales. The combined application of WSB and PRD can therefore emerge as a promising approach for improving the overall plant performance of maize plants with increased stomatal adaptations and WUE especially under water-limited conditions.

Gene expression pattern of K transporter GhHAK5 gene of potassium efficient and in-efficient cotton cultivars based on morphological physiognomies as affected by potassium nutrition and reduced irrigation

BackgroundUnder K deficiency the uptake and distribution pattern in plant cells is mediated through different transport proteins and channels which were controlled by specific gene family. Therefore, a hydroponic experiment was conducted under control condition for testing the gene expression pattern of the K transporter under adequate and low K supply levels. After that, a 2-year field experiment was conducted to evaluate five selected cotton cultivars (four K-efficient cultivars, viz., CIM-554, CYTO-124, FH-142, IUB-2013, and one K non-efficient, BH-212) screened from the initial hydroponics culture experiment and two levels of potassium (0 K2O kg·ha−1 and 50 K2O kg·ha−1) were tested under reduced irrigation (50% available water content; 50 AWC) and normal irrigation conditions (100% available water content; 100 AWC).ResultResults revealed that the transcript levels of GhHAK5aD in roots were significantly higher in K+ efficient cultivars than that in K+ non-efficient cultivars. The GhHAK5aD expression upon K+ deficiency was higher in roots but lower in shoots, indicating that GhHAK5aD could have a role in K+ uptake in roots, instead of transport of K+ from root to shoot. Similarly, under field conditions the cultivar FH-142 showed an increase of 22.3%, 4.9%, 2.4%, and 1.4% as compared with BH-212, IUB-2013, CYTO-124, and CIM-554, respectively, in seed cotton yield (SCY) with K application under reduced irrigation conditions. With applied K, the FH-142 showed an increase in net photosynthetic rate by 57.3% as compared with the rest of the cultivars under reduced irrigation over K control. However, the overall performance indicators of K-efficient cultivars like FH-142, CYTO-124, CIM-554, and IUB-2013 were better than BH-212 (K in-efficient) under reduced irrigation conditions with applied K at 50 kg·ha−1. Fiber quality trait improved significantly with K application under water deficit. The increase in micronaire was 3.6%, 4.7%, 7.8%, 3.4%, and 6.7% in BH-212, IUB-2013, CIM-554, CYTO-124, and FH-142, respectively, with K application at 50 kg·ha−1 over without K application under reduced irrigation conditions during the cotton growing season. Similarly, the cultivars FH-142 increased by 12% with K application under reduced irrigation as compared with other cultivars. The performance of K-efficient cultivars under reduced irrigation conditions was 30% better in SCY and quality traits with the application of K at 50 kg·ha−1 as compared with K-non-efficient cultivars. Similarly, water use efficiency (WUE) (40.1%) and potassium use efficiency (KUE) (20.2%) were also noted higher in case of FH-142 as compared with other cultivar with K application under reduced conditions.ConclusionHigher expression of GhHAK5aD gene was observed in K-efficient cultivars as compared with K-non-efficient cultivars in roots indicates that GhHAK5aD may be contributing to genotypic differences for K+ efficiency in cotton. K-efficient cotton cultivars can be used for the low-K environments and can also be recommended for general cultivars.

Growth and Performance of Guar (Cyamopsis tetragonoloba (L.) Taub.) Genotypes under Various Irrigation Regimes with and without Biogenic Silica Amendment in Arid Southwest US.

Guar is a potential crop that can be grown as a forage or as a seed crop in arid to semi-arid regions due to its low water requirements and tolerance to heat. Optimizing irrigation water use is important for making alternative crops such as guar a sustainable option. Amendments such as biogenic silica, a sedimentary rock from a biogenic source such as fossils, may help plants tolerate water stress due to reduced irrigation. The objective of the current study was to evaluate seed yield and attribute components and agronomic and physiological parameters for four guar genotypes (Matador, Kinman, Lewis, and NMSU 15-G1) under five drip irrigation regimes (I1-normal irrigation, I2-no irrigation at 75% pod formation, I3-no irrigation at 50% and 75% pod formation, I4-terminate irrigation at flowering, and I5-terminate irrigation at flowering + biogenic silica amendment) at Las Cruces in southern New Mexico, USA, from 2016 to 2018. On average, the I1 irrigation regime produced the highest guar seed yield (2715 kg ha-1) followed by I5 (2469 kg ha-1) from 2016 to 2018. As compared to the I1 regime, the I2 and I3 regimes resulted in a 20.8% and 23.4% decline in guar seed yield, respectively, on average from 2016 to 2018. The results suggest that the addition of biogenic silica might help to improve guar seed yield under reduced irrigation conditions and can produce comparable yields with an average of 300 mm of irrigation during the growing season in the southern New Mexico region of the Southwest US.

Enhanced fruit yield and quality of tomato by photosynthetic bacteria and CO2 enrichment under reduced irrigation

Reduced irrigation generally induces the tomato fruit yield reduction but enhance the fruit quality. Elevated CO2 (eCO2) injection is a common technique for alleviating water stress while eCO2 could inevitably lead to the element concentration dilution in the plant organs. Inoculated with photosynthetic bacteria (PSB) are confirmed to form a symbiotic relationship with crop roots, thereby promoting root development, and improving crop root nutrient and water uptake capacity. Yet, it remains unknown whether PSB could mitigate the adversely effect of nutrient dilution under eCO2 condition and the yield decline under reduced irrigation. To investigate that, two water treatments, including reduced irrigation (RI, plants were irrigated to 75% field water capacity) and full irrigation (FI, plants were irrigated to 90% field water capacity) of tomato plants, were grown under normal ambient CO2 (aCO2, 400 ppm) and elevated CO2 (eCO2, 800 ppm) conditions, respectively. And photosynthetic bacteria were inoculated in half plants. The results showed that inoculation of PSB improved the effectiveness of CO2 stimulation on biomass and yield in tomato plants grown under reduced irrigation conditions. The stimulation effects have been associated with increased advantages linked to their root system, we have observed that CO2 and PSB inoculation promoted the root development and antioxidant abilities. These consequently increased nitrogen uptake efficiency under eCO2 and reduced irrigation conditions, and increased nitrogen accumulation in various organs. Furthermore, eCO2 and inoculation with PSB individually or in combination ameliorated yield penalties under reduced irrigation conditions. Combined elevated CO2 and inoculation with PSB resulted in the highest fruit quality. Collectively, the responses of tomato fruit yield and quality to water-reduced irrigation regimes are further enhanced by the combination of eCO2 and PSB inoculation, and this would be efficacious in greenhouse tomato cultivation and future agriculture production.

Value-added products from wastewater reduce irrigation needs of Arundo donax energy crop.

Irrigation restrictions due to drought periods related to climate change, would affect different crops, especially to non-food crops. In this regard the effect of irrigation reduction should be studied in energy crops in order to obtain a sustainable bioenergy cropping system. Arundo donax, has been considered a crop with high water requirements, it has nevertheless been proven to be drought tolerant. However, there is a lack of knowledge on the effect of reduced irrigation combined with the use of different fertilizers. This work studied the combined effect of value-added products (VAPs) from wastewater (treated sewage sludge) or traditional inorganic fertilizers, and irrigation reduction in Arundo donax crop in a 2-year pot experiment. Plant biometric characteristics, chemical properties and biomass yield were studied as well as the effect of treatment on soil properties. Results showed that under reduced irrigation conditions, biomass production was reduced, especially during the second year. Organic treatments from sewage sludge minimize the effect of irrigation reduction. In these treatments, biomass yield for reduced irrigation was similar to that of the control treatment with irrigation at field capacity. For this reason, it is recommended to use VAPs from wastewater as organic amendments enabling water restriction with lower effect on Arundo production.

Pyrolysis GC/MS analysis of improved guayule genotypes

In addition to the commonly known use as an alternative source for natural rubber and hypoallergenic latex, guayule could also be a source of resin and bagasse for use in the pharmaceutical and biofuel industries. Pyrolysis is a method to convert guayule biomass into liquid (condensable gas or bio-oil), which can be an intermediate towards production of biofuels and/or renewable chemicals. In this work, six guayule genotypes that were planted under either well-irrigated or reduced-irrigation conditions were pyrolyzed using a pyrolysis gas-chromatography-mass spectrometry instrument (PY-GC/MS). The products included condensable gas, non-condensable gas and bio-char. Within the condensable gases, selected compounds were divided into nine chemical classes including aromatic hydrocarbons, alkyl phenols, guaiacols, syringols, furans, cyclopentenones, acetic acid and acetol, levoglucosan and limonene groups. As a result, significant variations were observed in the major compounds and prominent sub-constituents of condensable gas among the studied guayule genotypes and under irrigation levels. Strong positive correlations were found between irrigation levels and oxygenated condensable gas components derived from cellulose and lignin, although hydrocarbon components derived from the rubber and resin were found to be negatively correlated with irrigation levels. Results indicated that the genetic variations among guayule genotypes can be used to improve its bioenergy potential, and positive correlations observed among pyrolysis byproducts suggest the possibility to improve several byproducts simultaneously in guayule breeding programs. This research gives an insight to breed for guayule as an economic crop with high bioenergy potential for the development of sustainable agriculture.

YIELD FORMATION CAPACITY, SOIL WATER CONSUMPTION PROPERTY, AND PLANT WATER USE EFFICIENCY OF WHEAT UNDER WATER-SAVING CONDITIONS IN NORTH CHINA PLAIN

The drastically reduced underground water and shortage of the water resource have caused limitation for the winter wheat (T. aestivum) production in North China Plain. In this study, using a drought-tolerant wheat cultivar Shimai 18 as material, we investigated the yield formation capacity, soil water consumption property, and the plant water use efficiency (WUE) of wheat under various irrigation treatments. Our results indicated that the yield capacities of wheat varied largely across irrigation treatments in three growth seasons with contrasting precipitation patterns. The wheat yields showed constant in growth season with more rainfall and lowered to some extent in seasons with regular or less rainfall under I1 (water-saving condition with one time of irrigation) compared with I3 (regular irrigation with three times of irrigation). Along with increase of the irrigation times, plant WUE lowered drastically in all of three growth seasons examined, together with significantly increased evapotranspiration (ET) amount and relative constant of soil water deposits. These results suggested that the water-saving management is feasible in the winter wheat production in North China Plain. Additionally, the plant leaf area index (LAI), dry matter accumulation, and biomass partitioning rate of vegetative tissues during late growth stage (from flowering to maturity) were consistent with the yield formation capacities of the wheat cultivar. Our investigation indicates that the water-saving management using drought tolerant cultivars is effective in production of winter wheat in North China Plain, which can drastically improve the plant WUE and maintain the sustainable wheat productivity under reduced irrigation conditions.

Effect of TiO2 nanoparticles in thyme under reduced irrigation conditions

The nanotechnology is a relatively new technology that has recently entered the field of agriculture. Nanotechnology covers the integration or manipulation of individual atoms, molecules or molecular masses to a diverse array of structures allowing the production of new characteristics and traits of interest. The aim of this study was to evaluate the effects of foliar application of TiO2 nanoparticles on quantitative traits (plant height, number of branches, dry weight of shoots and roots) and the essential oil content of thyme under different levels of field capacity. Our results showed that the application of TiO2 nanoparticles had significant effects on thyme growth, while the essential oil concentrations not affected. These results imply that the application of TiO2 nanoparticles in plants increase agronomic value under reduced irrigation conditions but has not different significant on essential oil.

Essential oil composition and total phenolic, flavonoid contents, and antioxidant activity of sage (Salvia officinalis L.) extract under chitosan application and irrigation frequencies

Sage (Salvia officinalis L.), which is one of the most important pharmaceutical herbs, has been exploited for many uses. It is an important industrial crop that natural products in the form of extracts and essential oil from the leaves of this herb are used in pharmaceutical, perfumery, and food industries. Response of sage to foliar application of chitosan (control, 0.0, 0.25 and 0.50 g/L), a marine polysaccharide with unique bioactive properties, under three irrigation frequencies (4, 6, and 8 every days) was evaluated in an experimental field at semiarid and cold climate, Southwestern of Iran. Chitosan and irrigation frequencies treatments had significant effects on studied parameters, including quantity and quality of essential oil, antioxidant activities, and the amounts of total phenolic and flavonoids of the extract of sage. The results clearly indicated that application of chitosan was beneficial to plants under deficit irrigation treatments. The foliar application of chitosan reduced the adverse effect of reduced irrigation on essential oil yield and improved content of the essential oil. Elicitation of sage with chitosan had positive influences on the amounts of secondary metabolites, such as α-pinene, β-pinene, limonene, α-thujone, β-thujone, camphor, and 1,8-cineole in the essential oil from sage under reduced irrigation. In reduced irrigation conditions, the antioxidant activity, and the amounts of total phenolic and flavonoid of the extracts increased when the plants were sprayed with chitosan. In conclusion, results of this study indicated that the spray of chitosan elicitor can be have useful impacts on the essential oil quality and quantity, antioxidant activity, and the amounts of total phenolic and flavonoid of sage under reduced irrigation conditions or drought stress.

Evaluation of Agrostis Species and Cultivars and a Wetting Agent for Use on Golf Course Fairways under Reduced Irrigation

Optimization of management practices and selection of turfgrasses with traits that help to prolong turf quality and function under drought stress are important factors for turfgrass success under reduced irrigation conditions. The primary objectives of our research were to evaluate the performance of standard and improved cultivars of three bentgrass (Agrostis L. spp.) species in response to a wetting agent and reduced irrigation under fairway conditions. Turfgrasses included ‘Penncross’, ‘L‐93’, ‘13M’, and ‘T‐1’ creeping bentgrass (Agrostis stolonifera L.), ‘Tiger II’ and ‘Revere’ colonial bentgrass (Agrostis capillaris L.), and ‘Greenwich’ and ‘Legendary’ velvet bentgrass (Agrostis canina L.). Irrigation treatments were conducted from June through August in 2011 and 2012 and included: (i) a well‐watered (WW) irrigated control and no wetting agent application; (ii) a drought (DRT) treatment that received no irrigation and no wetting agent; and (iii) a drought treatment with no irrigation but received two pre‐applications of a wetting agent (DRT+WA). Withholding irrigation in the DRT and DRT+WA treatments resulted in a decline in volumetric soil moisture content, visual turf quality (TQ), and normalized difference vegetation index (NDVI) compared with WW plots; however, there were no significant differences in any of these parameters between DRT and DRT+WA in either year. Among the species, colonial bentgrass generally exhibited the highest TQ and velvet bentgrass the lowest TQ, which was associated with significantly higher thatch content (∼30%) for velvet bentgrass compared with other cultivars. Among the creeping bentgrass cultivars, T‐1 and 13M generally exhibited the highest TQ and NDVI, but were not significantly different from colonial bentgrass cultivars irrespective of irrigation regime.

Water-Deficit Inducible Expression of a Cytokinin Biosynthetic Gene IPT Improves Drought Tolerance in Cotton

Water-deficit stress is a major environmental factor that limits agricultural productivity worldwide. Recent episodes of extreme drought have severely affected cotton production in the Southwestern USA. There is a pressing need to develop cotton varieties with improved tolerance to water-deficit stress for sustainable production in water-limited regions. One approach to engineer drought tolerance is by delaying drought-induced senescence via up-regulation of cytokinin biosynthesis. The isopentenyltransferase gene (IPT) that encodes a rate limiting enzyme in cytokinin biosynthesis, under the control of a water-deficit responsive and maturation specific promoter PSARK was introduced into cotton and the performance of the PSARK::IPT transgenic cotton plants was analyzed in the greenhouse and growth chamber conditions. The data indicate that PSARK::IPT-transgenic cotton plants displayed delayed senescence under water deficit conditions in the greenhouse. These plants produced more root and shoot biomass, dropped fewer flowers, maintained higher chlorophyll content, and higher photosynthetic rates under reduced irrigation conditions in comparison to wild-type and segregated non-transgenic lines. Furthermore, PSARK::IPT-transgenic cotton plants grown in growth chamber condition also displayed greater drought tolerance. These results indicate that water-deficit induced expression of an isopentenyltransferase gene in cotton could significantly improve drought tolerance.

Genetic Engineering Peanut for Higher Drought- and Salt-Tolerance

Peanut (Arachis hypogaea L.) is one of the major oilseed crops, mainly grown in tropical and sub-tropical regions of the world. It is also rich in proteins, vitamins and ions, therefore it constitutes an important portion of food nutrition for people in these regions. The production of peanut is being threatened by the changing environments as the major peanut producing counties such as China, India, and USA are facing severe water shortage for peanut irrigation. The yield and quality of peanut are negatively affected by drought and salinity. Making peanut more droughtand salt-tolerant will likely sustain peanut production in countries where water shortage or saline soil are already problems. Efforts were made to genetically engineer peanut for higher tolerance to drought and salt. Analysis of these transgenic peanut plants indicated that the agronomic traits such as peanut yields were the same between wild-type and transgenic peanut plants under normal growth conditions, yet the yields of transgenic peanut plants were much higher than wild-type peanut plant under reduced irrigation conditions. Other traits such as protein content and fatty acid compositions in the seeds of transgenic peanut plants were not altered under both normal and drought conditions, indicating that the genetic manipulation of peanut for stress tolerance did not affect chemical compositions of peanut seeds in transgenic peanut plants, only increased seed yields under stress conditions.

Regulated Expression of an Isopentenyltransferase Gene (IPT) in Peanut Significantly Improves Drought Tolerance and Increases Yield Under Field Conditions

Isopentenyltransferase (IPT) is a critical enzyme in the cytokinin biosynthetic pathway. The expression of IPT under the control of a maturation- and stress-induced promoter was shown to delay stress-induced plant senescence that resulted in an enhanced drought tolerance in both monocot and dicot plants. This report extends the earlier findings in tobacco and rice to peanut (Arachis hypogaea L.), an important oil crop and protein source. Regulated expression of IPT in peanut significantly improved drought tolerance in both laboratory and field conditions. Transgenic peanut plants maintained higher photosynthetic rates, higher stomatal conductance and higher transpiration than wild-type control plants under reduced irrigation conditions. More importantly, transgenic peanut plants produced significantly higher yields than wild-type control plants in the field, indicating a great potential for the development of crops with improved performance and yield in water-limited areas of the world.

Expression of an Arabidopsis vacuolar H+‐pyrophosphatase gene (AVP1) in cotton improves drought‐ and salt tolerance and increases fibre yield in the field conditions

The Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump on the vacuolar membrane. Overexpression of AVP1 in Arabidopsis, tomato and rice enhances plant performance under salt and drought stress conditions, because up-regulation of the type I H+-PPase from Arabidopsis may result in a higher proton electrochemical gradient, which facilitates enhanced sequestering of ions and sugars into the vacuole, reducing water potential and resulting in increased drought- and salt tolerance when compared to wild-type plants. Furthermore, overexpression of AVP1 stimulates auxin transport in the root system and leads to larger root systems, which helps transgenic plants absorb water more efficiently under drought conditions. Using the same approach, AVP1-expressing cotton plants were created and tested for their performance under high-salt and reduced irrigation conditions. The AVP1-expressing cotton plants showed more vigorous growth than wild-type plants in the presence of 200 mM NaCl under hydroponic growth conditions. The soil-grown AVP1-expressing cotton plants also displayed significantly improved tolerance to both drought and salt stresses in greenhouse conditions. Furthermore, the fibre yield of AVP1-expressing cotton plants is at least 20% higher than that of wild-type plants under dry-land conditions in the field. This research indicates that AVP1 has the potential to be used for improving crop's drought- and salt tolerance in areas where water and salinity are limiting factors for agricultural productivity.

The Potential of Using Spectral Reflectance Indices to Estimate Yield in Wheat Grown Under Reduced Irrigation

The objectives of this research were to study the association in bread wheat between spectral reflectance indices (SRIs) and grain yield, estimate their heritability, and correlated response to selection (CR) for grain yield estimated from SRIs under reduced irrigation conditions. Reflectance was measured at three different growth stages (booting, heading and grainfilling) and five SRIs were calculated, namely normalized difference vegetation index (NDVI), simple ratio (SR), water index (WI), normalized water index-1 (NWI-1), and normalized water index-2 (NWI-2). Three field experiments were conducted (each with 30 advanced lines) in three different years. Two reduced irrigation environments were created: (1) one-irrigation level (pre-planting), and (2) two-irrigation level (pre-planting and at booting stage), both representing levels of reduced moisture. Maximum yield levels in the experimental zone were generally obtained with 4–6 irrigations. Genotypic variations for all SRIs were significant. Three NIR (near infrared radiation) based indices (WI, NWI-1, and NWI-2) gave the highest level of association (both phenotypic and genotypic) with grain yield under both reduced irrigation environments. Use of the mean SRI values averaged over growth stages and the progressive integration of SRIs from booting to grainfilling increased the capacity to explain variation among genotypes for yield under these reduced irrigation conditions. A higher level of broad-sense heritability was found with the two-irrigation environment (0.80) than with the one-irrigation environment (0.63). Overall, 50% to 75% of the 12.5% highest yielding genotypes, and 50% to 87% of the 25% highest yielding genotypes were selected when the NWI-2 index was applied as an indirect selection tool. Strong genetic correlations, moderate to high heritability, a correlated response for grain yield close to direct selection for grain yield, and a very high efficiency of selecting superior genotypes indicate the potential of using these three SRIs in breeding programs for selecting increased genetic gains in grain yield under reduced irrigation conditions.

Agronomic Performance of Related Durum Wheat (Triticum turgidum L.) Stocks Possessing the Chromosome Substitution T1BL.1RS

Comparisons of bread wheat (Triticum aestivum L.) germplasms provided evidence that the T1BL.1RS chromosome substitution enhances agronomic performance and, particularly, grain yield. There are no known reports of the effect of this translocation in durum wheat (Triticum turgidum L.), however. The objective of this study was to determine the effect of the T1BL.1RS chromosome on grain yield, yield components, and other agronomic traits using 22 related durum lines (11 homozygous for chromosome 1B, and 11 homozygous for T1BL.1RS). The test lines were produced by substituting the T1BL.1RS chromosome in T. turgidum cultivar Altar 84 (1B, 1B) through backcrossing. Two field trials were evaluated under optimum (five irrigations) and reduced (one irrigation) moisture conditions at the Mexican National Institute of Forestry, Agriculture and Livestock, Campo Agricola Experimental Valle del Yaqui (CAEVY) Research Center, Sonora, Mexico, during the 1993–1994 and 1994–1995 crop production cycles. The results indicated that the T1BL.1RS genotypes have increased above‐ground biomass at maturity, increased 1000‐kernel weight, and increased test weight in both irrigation treatments. The T1BL.1RS lines also possessed longer spikes and headed and matured later. The 1B lines produced more kernels m−2 than the T1BL.1RS lines in all tests, however. The yield superiority and longer grainfilling period of the T1BL.1RS translocation group were detected only under reduced irrigation conditions. The average effect of T1BL.1RS across years and irrigation treatments was to increase grain yield and aerial biomass by 3.5 and 3.3%, respectively. The yield advantage was attributed to increased kernel weight, test weight, and spike length.

The effect of chromosome 1AL/1RS translocation on agronomic performance of 85 F2-derived F6 lines from three Triticum aestivum L. crosses

The effect of the 1AL/1RS chromosome translocation on grain yield and other agronomic characteristics of 85 random F2-derived F6 bulks from three 1AL 1RS × 1A bread wheat crosses was determined under optimum and reduced irrigation conditions at CIANO, Yaqui Valley, Sonora, Mexico, during the 1991–1992 and 1992–1993 crop production cycles. Harvest plots of 5.0 m2 were arranged in an alpha lattice design with three replications. The 1AL/1RS translocation increased grain yield, above-ground biomass, spikes/m2, and test weight under both irrigated and dryland conditions. Homozygous chromosome 1A lines, on the other hand, possessed longer spikes with more grains. The 1AL/1RS cultivars had an advantage in 1000-grain weight, which was detected only under optimum irrigation. The translocation lines showed later maturity and longer grainfilling period than the 1A genotypes under one irrigation treatment. A significant relationship between grain yield and test weight was detected only among the 1AL/1RS genotypes, indicating that they possess heavier and plumper grains than the 1A genotypes. These results encourage the continued use of the 1AL/1RS translocation in wheat improvement.

The 1BL/1RS chromosome translocation effect on yield characteristics in a Triticum aestivum L. cross

AbstractComparisons involving 28 random F2‐derived F6 wheat (Triticum aestivum L.) lines from the cross, ‘Nacozari’/‘Seri 82’, suggested that advanced derivatives with the 1BL/1RS chromosome translocation possess superior agronomic performance in both full and reduced irrigation conditions when compared with 1B derivatives. This performance advantage was attributed to high grain yield, above‐ground biomass at maturity, grains/spike, 1000‐grain weight and test weight. The 1BL/1RS lines were shorter with delayed flowering and maturity. The superiority of the 1BL/1RS translocation group on grains/m2 was expressed only under the full irrigation environment. Higher harvest index, longer spike‐length and grain‐filling period were detected only under reduced irrigation conditions. A significant grain yield relationship with test weight was detected only among the 1BL/1RS genotypes, indicating that they possess heavier and plumper grains than the 1B genotypes.