Is transpiration efficiency a viable plant trait in breeding for crop improvement?

2012 ◽  
Vol 39 (5) ◽  
pp. 359 ◽  
Author(s):  
Thomas R. Sinclair

Increased transpiration efficiency – commonly the ratio of mass accumulation to transpiration – is often suggested as a critical opportunity for genetic improvement for increased crop yields in water-limited environments. However, close inspection of transpiration efficiency (TE) shows that it is a complex term that is explicitly dependent upon both physiological and environmental variables. Physiological variables include leaf photosynthetic capacity, biochemical composition of the plant productions and possible hydraulic limitation on water flow in the plant. Environmental variables include atmospheric CO2 concentration and atmospheric vapour pressure deficit. To complicate the resolution of transpiration efficiency, a weighted integration over the daily cycle and over the dates of interest needs to be resolved. Consequently, it is concluded that transpiration efficiency is not a variable easily resolved for use in many breeding programs. Instead, component traits contributing to TE need to be studied to increase the effective use of available water through the growing season to ultimately maximise growth and yield of the crop.

1995 ◽  
Vol 46 (1) ◽  
pp. 49 ◽  
Author(s):  
s Thoma ◽  
S Fukai

Two cultivars of barley and one cultivar of chickpea were grown in both well-watered and water stress conditions in three experiments. Water use efficiency (biomass produced per unit evapotranspiration) was lower in chickpea than in barley, and between two barley cultivars it was higher in early-maturing Corvette than in late-maturing Triumph. These differences in water use efficiency were mostly related to the differences in transpiration efficiency (biomass produced per unit transpiration). The latter appeared to reflect the differences in biomass production under well-watered conditions, as similar differences were found in light use efficiency (biomass produced per unit of photosynthetically active radiation intercepted) among the three crops. Transpiration efficiency was inversely related to vapour pressure deficit of the air. In three experiments soil evaporation accounted for about 55% and 10-30% of total water use for chickpea and barley respectively during observation periods, when rainfall was excluded from the plots. Slow canopy development of chickpea was a reason for such a high proportion of soil evaporation, and this contributed to its lower water use efficiency compared to barley. The amount of radiation transmitted to the soil surface appeared to be an important factor determining soil evaporation, even when soil water was not fully available and limiting soil evaporation.


2021 ◽  
Vol 22 (8) ◽  
pp. 3936
Author(s):  
Ahmed G. Gad ◽  
Habiba ◽  
Xiangzi Zheng ◽  
Ying Miao

Leaf senescence, as an integral part of the final development stage for plants, primarily remobilizes nutrients from the sources to the sinks in response to different stressors. The premature senescence of leaves is a critical challenge that causes significant economic losses in terms of crop yields. Although low light causes losses of up to 50% and affects rice yield and quality, its regulatory mechanisms remain poorly elucidated. Darkness-mediated premature leaf senescence is a well-studied stressor. It initiates the expression of senescence-associated genes (SAGs), which have been implicated in chlorophyll breakdown and degradation. The molecular and biochemical regulatory mechanisms of premature leaf senescence show significant levels of redundant biomass in complex pathways. Thus, clarifying the regulatory mechanisms of low-light/dark-induced senescence may be conducive to developing strategies for rice crop improvement. This review describes the recent molecular regulatory mechanisms associated with low-light response and dark-induced senescence (DIS), and their effects on plastid signaling and photosynthesis-mediated processes, chloroplast and protein degradation, as well as hormonal and transcriptional regulation in rice.


Author(s):  
Shinta Lestari Santosa ◽  
I Nyoman Rai ◽  
Wayan Diara

Vegetable cultivation is livelihoods for side Lake Batur communities, Kintamani, Bangli. Hilly natural conditions with a soil texture influenced by the eruption of Mount Batur, 900 m above sea level, and 900-3500 mm high rainfall, causing this region is very suitable for the cultivation of various vegetables, including shallot. One effort to meet the high demand for shallots is that efforts are made to improve cultivation techniques, including fertilizing to improve yields. In modern agriculture, the use of fertilizer is absolutely essential to trigger the level of crop production. The aims is to analyze the combination effect of using of inorganic fertilizer (ZA fertilizer) and organic fertilizer (compost fertilizer) on shallot vegetable cultivation systems on the content of pollutants, N nutrients and onion crop yields on the shores of Lake Batur, Kintamani District, Bangli Regency. The study using RBD with two factors where factor I: provision of organic fertilizer is leaf compost made aerobically (O), consisted of 3 levels, namely: O0 = 0*, O1 = 5* and O2 = 10*and factor II: the application of inorganic fertilizer namely ZA (S) fertilizer, consisted of 3 levels, namely: S0 = 0**, S1 = 50** and S2  = 100**, each repeated 3 times. The parameters observed were the growth and yield of shallots as well as the content of Pb, Zn, Cu and N nutrients in the soil. The nutrient content (N) in the soil, when using chemical fertilizer ZA and compost organic is not significantly different, as well as the results of onion plants, while the content of Pb, Zn and Cu on the use of chemical fertilizer ZA and organic compost, very real different. The highest soil Pb content in S2O1 treatment is 30.07***, the highest soil Zn content in the S2O1 treatment was 28.24***, and the highest soil Cu content in the S1O2 treatment is 17.22***. *= tons/ha **= kg/ha ***= mg/kg Keywords: compost; contents Pb; Zn; Cu of soil; shallot; ZA.


2021 ◽  
Author(s):  
Pablo Affortit ◽  
Branly Effa Effa ◽  
Mame Sokhatil Ndoye ◽  
Daniel Moukouanga ◽  
Nathalie Luchaire ◽  
...  

Because water availability is the most important environmental factor limiting crop production, improving water use efficiency, the amount of carbon fixed per water used, is a major target for crop improvement. In rice, the genetic bases of transpiration efficiency, the derivation of water use efficiency at the whole-plant scale, and its putative component trait transpiration restriction under high evaporative demand, remain unknown. These traits were measured in a panel of 147 African rice Oryza glaberrima genotypes, known as potential sources of tolerance genes to biotic and abiotic stresses. Our results reveal that higher transpiration efficiency is associated with transpiration restriction in African rice. Detailed measurements in a subset of highly differentiated genotypes confirmed these associations and suggested that the root to shoot ratio played an important role in transpiration restriction. Genome wide association studies identified marker-trait associations for transpiration response to evaporative demand, transpiration efficiency and its residuals, that links to genes involved in water transport and cell wall patterning. Our data suggest that root shoot partitioning is an important component of transpiration restriction that has a positive effect on transpiration efficiency in African rice. Both traits are heritable and define targets for breeding rice with improved water use strategies.


2020 ◽  
Author(s):  
Jie Wu ◽  
Zi-Sheng Zhang ◽  
Jing-Qiu Xia ◽  
Alamin Alfatih ◽  
Ying Song ◽  
...  

AbstractNitrogen (N) is one of the key essential macronutrients that affects rice growth and yield. Inorganic N fertilizers are excessively used to boost yield and generate serious collateral environmental pollution. Therefore, improving crop N use efficiency (NUE) is highly desirable and has been a major endeavor in crop improvement. However, only a few regulators have been identified that can be used to improve NUE in rice to date. Here we show that the NIN-like protein OsNLP4 significantly improves the rice NUE and yield. Field trials consistently showed that loss-of-OsNLP4 dramatically reduced yield and NUE compared with wild type under different N regimes. In contrast, the OsNLP4 overexpression lines remarkably increased yield by 30% and NUE by 47% under moderate N level compared with wild type. Transcriptomic analyses revealed that OsNLP4 orchestrates the expression of a majority of known N uptake, assimilation and signaling genes by directly binding to the nitrate-responsive cis-element in their promoters to regulate their expression. Moreover, overexpression of OsNLP4 can recover the phenotype of Arabidopsis nlp7 mutant and enhance its biomass. Our results demonstrate that OsNLP4 is a master regulator of NUE in rice and sheds light on crop NUE improvement.


2019 ◽  
Vol 11 (9) ◽  
pp. 272
Author(s):  
Milena Barretta Franceschetti ◽  
Leandro Galon ◽  
Maico André Michelon Bagnara ◽  
Renan Pawelkiewicz ◽  
Leonardo Brunetto ◽  
...  

Among the factors which affect crop productivity, there are weeds which compete for environment resources. The objective of this work was to determine the periods of interference of alexandergrass on the morphophysiology and productivity components of black beans. The experiment was conducted in a complete randomized block design with four replications. The bean cultivar of the black type used was IPR Uirapuru, being the treatments separated in two models of interference: in the coexistence group, the crop of the bean lived with the alexandergrass by growing periods of 0, 7, 14, 21, 28, 35, 42 and throughout the cycledays after emergence and throughout the cycle; in the control group the crop was kept free of the infestation for the same periods described previously. At 42 DAE were evaluated the variables related to plant morphology and physiology (height of bean plants, number of trifoliate leaves, dry mass plant, number of grains pods, number od pods plants, stomatal conductance, internal CO2 concentration, photosynthetic activity, efficiency of carboxylation, efficient use of water, transpiration rate). Considering the results, it is possible to conclude that the critical period of interference prevention (CPIP) comprises 24 to 50 DAE, the period before the interference (PBI) was 24 DAE and the total period of interference prevention (TPIP) was 50 days and that the morphological and physiological variables of the plants were negatively affected in the coexistence with the alexandergrass when compared to the treatments kept free of weeds throughout the crop cycle.


2019 ◽  
Vol 46 (12) ◽  
pp. 1072 ◽  
Author(s):  
Geetika Geetika ◽  
Erik J. van Oosterom ◽  
Barbara George-Jaeggli ◽  
Miranda Y. Mortlock ◽  
Kurt S. Deifel ◽  
...  

Water scarcity can limit sorghum (Sorghum bicolor (L.) Moench) production in dryland agriculture, but increased whole-plant transpiration efficiency (TEwp, biomass production per unit of water transpired) can enhance grain yield in such conditions. The objectives of this study were to quantify variation in TEwp for 27 sorghum genotypes and explore the linkages of this variation to responses of the underpinning leaf-level processes to environmental conditions. Individual plants were grown in large lysimeters in two well-watered experiments. Whole-plant transpiration per unit of green leaf area (TGLA) was monitored continuously and stomatal conductance and maximum photosynthetic capacity were measured during sunny conditions on recently expanded leaves. Leaf chlorophyll measurements of the upper five leaves of the main shoot were conducted during early grain filling. TEwp was determined at harvest. The results showed that diurnal patterns in TGLA were determined by vapour pressure deficit (VPD) and by the response of whole-plant conductance to radiation and VPD. Significant genotypic variation in the response of TGLA to VPD occurred and was related to genotypic differences in stomatal conductance. However, variation in TGLA explained only part of the variation in TEwp, with some of the residual variation explained by leaf chlorophyll readings, which were a reflection of photosynthetic capacity. Genotypes with different genetic background often differed in TEwp, TGLA and leaf chlorophyll, indicating potential differences in photosynthetic capacity among these groups. Observed differences in TEwp and its component traits can affect adaptation to drought stress.


2019 ◽  
Vol 116 (48) ◽  
pp. 24041-24048 ◽  
Author(s):  
Devendra Shivhare ◽  
Jediael Ng ◽  
Yi-Chin Candace Tsai ◽  
Oliver Mueller-Cajar

During photosynthesis the AAA+ protein and essential molecular chaperone Rubisco activase (Rca) constantly remodels inhibited active sites of the CO2-fixing enzyme Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase) to release tightly bound sugar phosphates. Higher plant Rca is a crop improvement target, but its mechanism remains poorly understood. Here we used structure-guided mutagenesis to probe the Rubisco-interacting surface of rice Rca. Mutations in Ser-23, Lys-148, and Arg-321 uncoupled adenosine triphosphatase and Rca activity, implicating them in the Rubisco interaction. Mutant doping experiments were used to evaluate a suite of known Rubisco-interacting residues for relative importance in the context of the functional hexamer. Hexamers containing some subunits that lack the Rubisco-interacting N-terminal domain displayed a ∼2-fold increase in Rca function. Overall Rubisco-interacting residues located toward the rim of the hexamer were found to be less critical to Rca function than those positioned toward the axial pore. Rca is a key regulator of the rate-limiting CO2-fixing reactions of photosynthesis. A detailed functional understanding will assist the ongoing endeavors to enhance crop CO2 assimilation rate, growth, and yield.


1990 ◽  
Vol 115 (3) ◽  
pp. 313-320 ◽  
Author(s):  
J. T. Baker ◽  
L. H. Allen ◽  
K. J. Boote

SUMMARYRice plants (Oryza salivaL., cv. IR30) were grown in paddy culture in outdoor, naturally sunlit, controlled-environment, plant growth chambers at Gainesville, Florida, USA, in 1987. The rice plants were exposed throughout the season to subambient (160 and 250), ambient (330) or superambient (500, 660, 900 μmol CO2/mol air) CO2concentrations. Total shoot biomass, root biomass, tillering, and final grain yield increased with increasing CO2concentration, thegreatest increase occurring between the 160 and 500 μmol CO2/mol air treatments. Early in the growing season, root:shoot biomass ratio increased with increasing CO2concentration; although the ratio decreased during the growing season, net assimilation rate increased with increasingCO2concentration and decreased during the growing season. Differences in biomass and lamina area among CO2treatments were largely due to corresponding differences in tillering response. The number of panicles/plant was almost entirely responsible for differences in final grain yield among CO2treatments. Doubling the CO2 concentration from 330 to 660 μmol CO2/mol air resulted in a 32 % increase in grain yield. These results suggest that important changes in the growth and yield of rice may be expected in the future as the CO2concentration of the earth's atmosphere continues to rise.


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