Physiological traits and cereal germplasm for sustainable agricultural systems

Richards, R. A.; Watt, Michelle; Rebetzke, G. J.

doi:10.1007/s10681-006-9286-1

Cited by 92 publications

(48 citation statements)

References 79 publications

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“…However, the significant genotypic variation observed for this trait means that genotypes with good partitioning efficiency for storage root expansion could be selected for further improvement. Though deeper storage roots may be good adaptation for survival under drought conditions in other crops [31][32][33], it could be detrimental in cassava if expansion in storage root girth is compromised. Root growth exhibits positive hydrotropism and gravitropism, therefore, there is a natural tendency for storage root extension to prevail over expansion due to the need to explore lower soil depths for moisture [21,34].…”

Section: Pattern Of Storage Root Bulkingmentioning

confidence: 99%

Genetic variability in storage root bulking of cassava genotypes under irrigation and no irrigation

et al. 2016

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Background: Early bulking in cassava (Manihot esculenta Crantz) is a very important trait in semi-arid ecologies of the tropics. Farmers tend to select early-maturing cassava varieties to escape terminal drought and destruction by domestic animals during the dry season. However, early harvesting is associated with yield penalty due to unavailability of high-yielding early-maturing cassava varieties. In order to develop early-bulking cassava varieties for the savanna ecologies, this study was carried out to assess genetic variation in the pattern of storage root bulking and as well as traits associated with early storage root bulking under moisture stress and well-watered conditions. Methods:Twenty cassava genotypes were arranged in a randomised complete block design with three replications under irrigation and no irrigation. The genotypes were sequentially harvested at 6, 8, 10 and 12 months after planting to study their pattern of dry matter accumulation. Irrigation water was supplied using a drip irrigation system with a discharge capacity of 1.6 l/h.Results: Analysis of variance indicated significant effect of genotype, harvesting time and irrigation on most of the yield traits studied. The interaction between genotype and irrigation effect was significant for all traits except mean storage root weight, storage root girth, storage root length and storage root dry matter content. Apart from storage root girth and storage root dry matter content, genotype × harvesting time interaction was not significant. Pearson correlation analysis of root yield at different times showed significant positive correlation between early storage root yield and final root yield indicating the possibility of selecting early-bulking genotypes with high yield potential. Conclusion:The study indicated that dry matter is partitioned more for root elongation than expansion in root girth under moisture stress conditions compared with irrigation, resulting in high storage root length: girth ratio. This ratio can be used to study the pattern of photosynthates accumulation in cassava roots under stress conditions. The study helped to provide improved understanding of the genetic basis and the mechanism of storage root bulking in cassava under moisture stress conditions, which can be exploited to develop high-yielding cassava varieties for droughtprone areas to ensure food security.

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Section: Pattern Of Storage Root Bulkingmentioning

confidence: 99%

Genetic variability in storage root bulking of cassava genotypes under irrigation and no irrigation

et al. 2016

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“…A relatively small gain in P recovery would translate into significant economic and environmental benefits, since P entering surface waters from runoff and erosion is a significant pollutant, and high-grade P ore deposits are a limited, non-renewable resource [7,8]. In many agricultural soils, an increase in crop rooting depth results in increased water acquisition [9]. Genotypic variation for soil resource acquisition may be largely untapped in crop breeding programmes which have historically focused on adaptation to high-input systems, and which have rarely used root traits as selection criteria.…”

Section: The Opportunitymentioning

confidence: 99%

New roots for agriculture: exploiting the root phenome

Lynch

Brown

2012

Phil. Trans. R. Soc. B

265

187

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Recent advances in root biology are making it possible to genetically design root systems with enhanced soil exploration and resource capture. These cultivars would have substantial value for improving food security in developing nations, where yields are limited by drought and low soil fertility, and would enhance the sustainability of intensive agriculture. Many of the phenes controlling soil resource capture are related to root architecture. We propose that a better understanding of the root phenome is needed to effectively translate genetic advances into improved crop cultivars. Elementary, unique root phenes need to be identified. We need to understand the 'fitness landscape' for these phenes: how they affect crop performance in an array of environments and phenotypes. Finally, we need to develop methods to measure phene expression rapidly and economically without artefacts. These challenges, especially mapping the fitness landscape, are non-trivial, and may warrant new research and training modalities.

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“…The tin plants produce larger aboveground organs, including reproductive structures, and they have a higher root-to-shoot ratio and a deeper root system than the wild type (Atsmon and Jacobs, 1977;Duggan et al, 2005;Richards et al, 2007). In the rice OsSPL14 mutants, the reduced tillering and increased panicle branching is due to the role of the gene during both the vegetative and reproductive phases (Jiao et al, 2010;Miura et al, 2010).…”

Section: Murraymentioning

confidence: 99%

Inhibition of Tiller Bud Outgrowth in thetinMutant of Wheat Is Associated with Precocious Internode Development

et al. 2012

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Tillering (branching) is a major yield component and, therefore, a target for improving the yield of crops. However, tillering is regulated by complex interactions of endogenous and environmental signals, and the knowledge required to achieve optimal tiller number through genetic and agronomic means is still lacking. Regulatory mechanisms may be revealed through physiological and molecular characterization of naturally occurring and induced tillering mutants in the major crops. Here we characterize a reduced tillering (tin, for tiller inhibition) mutant of wheat (Triticum aestivum). The reduced tillering in tin is due to early cessation of tiller bud outgrowth during the transition of the shoot apex from the vegetative to the reproductive stage. There was no observed difference in the development of the main stem shoot apex between tin and the wild type. However, tin initiated internode development earlier and, unlike the wild type, the basal internodes in tin were solid rather than hollow. We hypothesize that tin represents a novel type of reduced tillering mutant associated with precocious internode elongation that diverts sucrose (Suc) away from developing tillers. Consistent with this hypothesis, we have observed upregulation of a gene induced by Suc starvation, downregulation of a Suc-inducible gene, and a reduced Suc content in dormant tin buds. The increased expression of the wheat Dormancy-associated (DRM1-like) and Teosinte Branched1 (TB1-like) genes and the reduced expression of cell cycle genes also indicate bud dormancy in tin. These results highlight the significance of Suc in shoot branching and the possibility of optimizing tillering by manipulating the timing of internode elongation.

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Physiological traits and cereal germplasm for sustainable agricultural systems

Cited by 92 publications

References 79 publications

Genetic variability in storage root bulking of cassava genotypes under irrigation and no irrigation

Genetic variability in storage root bulking of cassava genotypes under irrigation and no irrigation

New roots for agriculture: exploiting the root phenome

Inhibition of Tiller Bud Outgrowth in thetinMutant of Wheat Is Associated with Precocious Internode Development

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