Special Issue: High-throughput Phenotyping for Breeding   

May 2014, Volume 56 Issue 5, Pages 422每515.

Cover Caption: High-throughput Phenotyping for Breeding
About the cover: Constraints in field phenotyping limit our ability to dissect complex quantitative traits, particularly those related to yield and stress tolerance. Effective field-based highthroughput phenotyping platforms remain a bottleneck for crop breeding. Progresses in remote-sensing, aeronautics and high-performance computing together with the emergence of affordable phenotyping tools have been developed. One example is the aerial platform developed with the support of the Global Maize Program of CIMMYT (cover image provided by Dr. Jos谷 Luis Araus).


Phenotyping and other breeding approaches for a New Green Revolution  
Author: Jose Luis Araus, Jiansheng Li, Martin A. J. Parry and Jiankang Wang
Journal of Integrative Plant Biology 2014 56(5): 422每424
Published Online: April 4, 2014
DOI: 10.1111/jipb.12202
Abstract (Browse 927)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Invited Expert Reviews
Progress in TILLING as a tool for functional genomics and improvement of crops  
Author: Liang Chen, Liugen Hao, Martin A. J. Parry, Andrew L. Phillips and Yin-Gang Hu
Journal of Integrative Plant Biology 2014 56(5): 425每443
Published Online: March 12, 2014
DOI: 10.1111/jipb.12192

Food security is a global concern and substantial yield increases in crops are required to feed the growing world population. Mutagenesis is an important tool in crop improvement and is free of the regulatory restrictions imposed on genetically modified organisms. Targeting Induced Local Lesions in Genomes (TILLING), which combines traditional chemical mutagenesis with high-throughput genome-wide screening for point mutations in desired genes, offers a powerful way to create novel mutant alleles for both functional genomics and improvement of crops. TILLING is generally applicable to genomes whether small or large, diploid or even allohexaploid, and shows great potential to address the major challenge of linking sequence information to the function of genes and to modulate key traits for plant breeding. TILLING has been successfully applied in many crop species and recent progress in TILLING is summarized below, especially on the developments in mutation detection technology, application of TILLING in gene functional studies and crop breeding. The potential of TILLING/EcoTILLING for functional genetics and crop improvement is also discussed. Furthermore, a small-scale forward strategy including backcross and selfing was conducted to release the potential mutant phenotypes masked in M2 (or M3) plants.

Abstract (Browse 933)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Research Articles
Contribution of the ear and the flag leaf to grain filling in durum wheat inferred from the carbon isotope signature: Genotypic and growing conditions effects  
Author: Rut Sanchez-Bragado, Abdelhalim Elazab, Bangwei Zhou, Maria Dolors Serret, Jordi Bort, Maria Teresa Nieto-Taladriz and José Luis Araus
Journal of Integrative Plant Biology 2014 56(5): 444每454
Published Online: September 9, 2013
DOI: 10.1111/jipb.12106
The ear, together with the flag leaf, is believed to play a major role as a source of assimilates during grain filling in C3 cereals. However, the intrusive nature of most of the available methodologies prevents reaching conclusive results in this regard. This study compares the carbon isotope composition (δ13C) in its natural abundance in the water-soluble fractions of the flag leaf blade and the ear with the δ13C of mature kernels to assess the relative contribution of both organs to grain filling in durum wheat (Triticum turgidum L. var. durum). The relative contribution of the ear was higher in landraces compared to modern cultivars, as well as in response to nitrogen fertilization and water stress. Such genotypic and environmentally driven differences were associated with changes in harvest index (HI), with the relative contribution of the ear being negatively associated with HI. In the case of the genotypic differences, the lower relative contribution of the ear in modern cultivars compared with landraces is probably associated with the appearance in the former of a certain amount of source limitation driven by a higher HI. In fact, the relative contribution of the ear was far more responsive to changes in HI in modern cultivars compared with landraces.
Abstract (Browse 1198)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Quantifying relationships between rooting traits and water uptake under drought in Mediterranean barley and durum wheat  
Author: Pedro Carvalho, Sayed Azam-Ali and M. John Foulkes
Journal of Integrative Plant Biology 2014 56(5): 455每469
Published Online: September 30, 2013
DOI: 10.1111/jipb.12109

In Mediterranean regions drought is the major factor limiting spring barley and durum wheat grain yields. This study aimed to compare spring barley and durum wheat root and shoot responses to drought and quantify relationships between root traits and water uptake under terminal drought. One spring barley (Hordeum vulgare L. cv. Rum) and two durum wheat Mediterranean cultivars (Triticum turgidum L. var durum cvs Hourani and Karim) were examined in soil-column experiments under well watered and drought conditions. Root system architecture traits, water uptake, and plant growth were measured. Barley aerial biomass and grain yields were higher than for durum wheat cultivars in well watered conditions. Drought decreased grain yield more for barley (47%) than durum wheat (30%, Hourani). Root-to-shoot dry matter ratio increased for durum wheat under drought but not for barley, and root weight increased for wheat in response to drought but decreased for barley. The critical root length density (RLD) and root volume density (RVD) for 90% available water capture for wheat were similar to (cv. Hourani) or lower than (cv. Karim) for barley depending on wheat cultivar. For both species, RVD accounted for a slightly higher proportion of phenotypic variation in water uptake under drought than RLD.

Abstract (Browse 1023)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Wheat genotypic variability in grain yield and carbon isotope discrimination under Mediterranean conditions assessed by spectral reflectance  
Author: Gustavo A. Lobos, Iván Matus, Alejandra Rodriguez, Sebastián Romero-Bravo, José Luis Araus and Alejandro del Pozo
Journal of Integrative Plant Biology 2014 56(5): 470每479
Published Online: October 9, 2013
DOI: 10.1111/jipb.12114

A collection of 368 advanced lines and cultivars of spring wheat (Triticum aestivum L.) from Chile, Uruguay, and CIMMYT (Centro Internacional de Mejoramiento de Maíz y Trigo), with good agronomic characteristics were evaluated under the Mediterranean conditions of central Chile. Three different water regimes were assayed: severe water stress (SWS, rain fed), mild water stress (MWS; one irrigation around booting), and full irrigation (FI; four irrigations: at tillering, flag leaf appearance, heading, and middle grain filling). Traits evaluated were grain yield (GY), agronomical yield components, days from sowing to heading, carbon isotope discrimination (Δ13C) in kernels, and canopy spectral reflectance. Correlation analyses were performed for 70 spectral reflectance indices (SRI) and the other traits evaluated in the three trials. GY and Δ13C were the traits best correlated with SRI, particularly when these indices were measured during grain filling. However, only GY could be predicted using a single regression, with Normalized Difference Moisture Index (NDMI2: 2,200; 1,100) having the best fit to the data for the three trials. For Δ13C, only individual regressions could be forecast under FI (r2: 0.25–0.37) and MWS (r2: 0.45–0.59) but not under SWS (r2: 0.03–0.09). NIR-based SRI proved to be better predictors than those that combine visible and NIR wavelengths.

Abstract (Browse 1000)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Functional analyses of an E3 ligase gene AIP2 from wheat in Arabidopsis revealed its roles in seed germination and pre-harvest sprouting  
Author: Dong-Yao Gao, Zhao-Shi Xu, Yi He, Yong-Wei Sun, You-Zhi Ma and Lan-Qin Xia
Journal of Integrative Plant Biology 2014 56(5): 480每491
Published Online: November 26, 2013
DOI: 10.1111/jipb.12135

Pre-harvest sprouting (PHS) seriously affects wheat yield and quality of the grain. ABI3 is a key factor in the activation of seed development and repression of germination in Arabidopsis. An ABI3-interacting protein (AIP2) could polyubiquitinate ABI3, impair seed dormancy and promote seed germination in Arabidopsis. In this study, two wheat AIP2 genes, TaAIP2A and TaAIP2B, were isolated. Subcellular localization assay and yeast two-hybrid analysis revealed that TaAIP2A and TaAIP2B may function through interaction with wheat Viviporous-1 (TaVp1). The transcripts TaAIP2A and TaAIP2B were more abundant in wheat PHS susceptible cultivars than that of resistant ones, and decreased gradually following seed development. Expression of TaAIP2A and TaAIP2B in Arabidopsis aip2-1 mutant lines resulted in earlier flowering, promotion of seed germination, and reduced ABA sensitivity, respectively, somehow mimicking the phenotype of the wild type, with TaAIP2B having a stronger role in these aspects. Furthermore, the expression of upstream genes ABI1 and ABI2 were upregulated, whereas that of downstream genes ABI3 and ABI5 were downregulated in both TaAIP2A and TaAIP2B complemented lines upon ABA treatment. These results suggested that wheat AIP2s could negatively regulate the ABA signaling pathway and play important roles in seed germination, and thus wheat PHS resistance finally.

Abstract (Browse 1014)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Physiological traits contributed to the recent increase in yield potential of winter wheat from Henan Province, China  
Author: Bangwei Zhou, Álvaro Sanz-Sóez, Abdelhalim Elazab, Tianmin Shen, Rut Sónchez-Bragado, Jordi Bort, Maria Dolors Serret and José Luis Araus
Journal of Integrative Plant Biology 2014 56(5): 492每504
Published Online: December 20, 2013
DOI: 10.1111/jipb.12148
This experiment aims to test the traits responsible for the increase in yield potential of winter wheat released in Henan Province, China. Seven established cultivars released in the last 20 years and three advanced lines were assayed. The results showed that grain yield was positively correlated with harvest index (HI), kernel number per square meter, and aboveground biomass. In addition, the HI and aboveground biomass showed an increasing trend with the year of release. Therefore, we can conclude that bread wheat breeding advances during recent decades in Henan Province, China, have been achieved through an increase in HI, kernel number per square meter, and aboveground biomass. A higher δ13C seems also to be involved in these advances, which suggests a progressive improvement in constitutive water use efficiency not associated with a trend towards lower stomatal conductance in the most recent genotypes. However, genetic advance does not appear related to changes in photosynthesis rates on area basis when measured in the flag leaf or the spike, but only to a higher, whole-spike photosynthesis. Results also indirectly support the concept that under potential yield conditions, the spike contributed more than the flag leaf to kernel formation.


Abstract (Browse 1016)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Chlorophyll, anthocyanin, and gas exchange changes assessed by spectroradiometry in Fragaria chiloensis under salt stress  
Author: Miguel Garriga, Jorge B. Retamales, Sebastián Romero, Peter D.S. Caligari and Gustavo A. Lobos
Journal of Integrative Plant Biology 2014 56(5): 505每515
Published Online: March 12, 2014
DOI: 10.1111/jipb.12193

Chlorophyll and anthocyanin contents provide a valuable indicator of the status of a plant's physiology, but to be more widely utilized it needs to be assessed easily and non-destructively. This is particularly evident in terms of assessing and exploiting germplasm for plant-breeding programs. We report, for the first time, experiments with Fragaria chiloensis (L.) Duch. and the estimation of the effects of response to salinity stress (0, 30, and 60 mmol NaCl/L) in terms of these pigments content and gas exchange. It is shown that both pigments (which interestingly, themselves show a high correlation) give a good indication of stress response. Both pigments can be accurately predicted using spectral reflectance indices (SRI); however, the accuracy of the predictions was slightly improved using multilinear regression analysis models and genetic algorithm analysis. Specifically for chlorophyll content, unlike other species, the use of published SRI gave better indications of stress response than Normalized Difference Vegetation Index. The effect of salt on gas exchange is only evident at the highest concentration and some SRI gave better prediction performance than the known Photochemical Reflectance Index. This information will therefore be useful for identifying tolerant genotypes to salt stress for incorporation in breeding programs.

Abstract (Browse 993)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
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