Genotypic difference in root penetration ability by durum wheat (Triticum turgidum L. var. durum) evaluated by a pot with paraffin-Vaseline discs (original) (raw)
Related papers
Plant Production Science, 2008
Root growth into deep soil is an important factor for stable production in wheat under drought conditions. Root penetrating capacity (RP) shown by pot experiments with a paraffi n-Vaseline layer (PV layer) may be a useful indicator estimating deep rooting ability of wheat genotypes. Previously, we identifi ed genotypes of durum wheat (Triticum turgidum L. var. durum) and bread wheat (T. aestivum L.) with diverse RP by the pot experiments. In this study, we investigated the root distribution of three Ethiopian landraces of durum wheat with high RP, three recent cultivars of durum wheat with low RP and one Japanese cultivar of bread wheat 'Haruyutaka' with low RP using: (1) pots with a PV layer, (2) root boxes, (3) artifi cial fi eld and (4) a normal fi eld to analyze the relationship between RP estimated by pot experiment and root development in the fi eld. In the pot experiments, RP was evaluated by the number of roots penetrating through the PV layer (NRP). In the root-box and field experiments, the root distribution was evaluated by the number of roots on the vertical surface of soil as the root frequency (RF: root number cm-1 soil surface). Ethiopian landraces had a signifi cantly larger NRP than recent cultivars in the pot experiment. The root box and fi eld experiments showed that Ethiopian landraces tended to have a higher RF than recent cultivars in deep soil layer. We concluded that RP estimated by pot experiments with a PV layer is a useful indicator of deep rooting ability under fi eld conditions.
Plant Production Science, 2006
The hard soil in the fi eld is a major constraint for the cereal production because it mechanically restricts the root expansion and water absorption. The ability of root to penetrate into the hard soil is an important factor affecting yield stability of wheat (Triticum aestivum L.) under hard soil and drought conditions. We investigated the variation in the penetrating ability of roots (PA) among Japanese wheat cultivars and its relationship with other shoot and root characters to acquire basic information to develop the cultivars with a higher PA. The evaluation was conducted by the two experiments using the two groups of cultivars: 1) 43 Hokkaido cultivars in the fi rst experiment, 2) 38 Honsyu, including Shikoku and Kyusyu, cultivars in the second experiment. In each experiment, one seedling of each cultivar was grown in a pot with a disc made of paraffi n and Vaseline mixture (PV) as a substitute for the hard soil layer. The number of roots penetrating through the PV disc per plant (NRP), the number of seminal and crown roots reached the PV disc per plant (NRR) and the penetration index (PI = NRP/NRR) of each cultivar were evaluated as the traits related to PA. NRP signifi cantly varied with the cultivar from 4.0 to 29.7 and 3.0 to 22.0 in the fi rst and second experiments, respectively. NRP were signifi cantly correlated with NRR (r=0.644** in the fi rst and r=0.477** in the second experiment) and PI (r=0.863** in the fi rst and r=0.811** in the second experiment), but the relationships between NRR and PI were not signifi cant (r=0.260 in the fi rst and r=0.190 in the second experiment). NRR was signifi cantly correlated with the degree of winter growth habit (requirement of vernalization), root dry weight (DW) above the PV disc, the number of stems and leaf DW in each population. Correlations between PI and other characters were low or not signifi cant. These results indicate that a large genotypic variation exists among Japanese wheat cultivars in NRP, and that PI is a suitable indicator of PA. Cultivars with a high PA detected in this study will be useful genetic resources of wheat to improve the yield stability under drought and hard soil conditions.
Quantitative trait loci for soil-penetrating ability of roots in durum wheat
Plant Breeding, 2007
... Ishaq, M., M ... Nachit, MM, I. Elouafi, MA Pagnotta, A. El Saleh, E., Iacono, M., Labhilili, A., Asbati, M., Azrak, H., Hazzam, D., Benscher, M., Khairallah, JM, Ribaut, OA, Tanzarella, E., Porceddu, and ME Sorrells, 2001: Molecular linkage map for an interspecific recombinant inbred ...
Plant Production Science, 2006
The hard soil in the fi eld is a major constraint for the cereal production because it mechanically restricts the root expansion and water absorption. The ability of root to penetrate into the hard soil is an important factor affecting yield stability of wheat (Triticum aestivum L.) under hard soil and drought conditions. We investigated the variation in the penetrating ability of roots (PA) among Japanese wheat cultivars and its relationship with other shoot and root characters to acquire basic information to develop the cultivars with a higher PA. The evaluation was conducted by the two experiments using the two groups of cultivars: 1) 43 Hokkaido cultivars in the fi rst experiment, 2) 38 Honsyu, including Shikoku and Kyusyu, cultivars in the second experiment. In each experiment, one seedling of each cultivar was grown in a pot with a disc made of paraffi n and Vaseline mixture (PV) as a substitute for the hard soil layer. The number of roots penetrating through the PV disc per plant (NRP), the number of seminal and crown roots reached the PV disc per plant (NRR) and the penetration index (PI = NRP/NRR) of each cultivar were evaluated as the traits related to PA. NRP signifi cantly varied with the cultivar from 4.0 to 29.7 and 3.0 to 22.0 in the fi rst and second experiments, respectively. NRP were signifi cantly correlated with NRR (r=0.644** in the fi rst and r=0.477** in the second experiment) and PI (r=0.863** in the fi rst and r=0.811** in the second experiment), but the relationships between NRR and PI were not signifi cant (r=0.260 in the fi rst and r=0.190 in the second experiment). NRR was signifi cantly correlated with the degree of winter growth habit (requirement of vernalization), root dry weight (DW) above the PV disc, the number of stems and leaf DW in each population. Correlations between PI and other characters were low or not signifi cant. These results indicate that a large genotypic variation exists among Japanese wheat cultivars in NRP, and that PI is a suitable indicator of PA. Cultivars with a high PA detected in this study will be useful genetic resources of wheat to improve the yield stability under drought and hard soil conditions.
A Field Technique for Screening for Genotypic Differences in Root Growth 1
Crop Science, 1985
There is an interest in breeding for deep, extensive root systems to increase crop yields in semiarid environments. Our objective was to develop a field technique with which large numbers of genotypes could be tested for this trait. The experiments were conducted with cowpea (Vigna unguiculata [L.] Walp.) grown on stored soil moisture in the field (coarse-loamy, mixed, thermic Haplic Durixeralf). The herbicide, metribuzin, was banded into the root zone at sowing at specific depths and lateral distances from the seed rows. In the main field trial, lateral distances of 46, 61, and 76 cm were tested in combination with vertical herbicide bands of 30 and 15 cm at average vertical depths of 53 and 60 cm, respectively, and with herbicide rates of 4.5 and 9.0 kg active ingredient ha" 1 in the band. Plant leaves were observed for herbicide symptoms. With this technique, we succeeded in detecting the progress of root growth in the field. Herbicide symptoms consistently developed soonest in plants which were closest to the herbicide band, in either the horizontal or vertical direction. We also succeeded in detecting significant genotypic differences in mean numbers of days to first herbicide symptoms among five cowpea genotypes; California Blackeye #5 and Grant developed symptoms the earliest, 8006 and PI302457 developed symptoms the latest, and PI293579 was intermediate. With four replicates of two-row plots, mean genotypic differences of 2 to 3 days were usually significant at the 5% level. The ranking of genotypes obtained with this herbicide-band technique was consistent with estimates of relative depth of effective rooting obtained from soil moisture extraction measurements. Prior to using this technique in different environments, or to screen other crop species, tests should be conducted to determine the most appropriate herbicide, rate of application, and band location in the soil profile. This technique requires fairly uniform soil throughout the root zone, and relatively uniform genetic material. We conclude that this herbicide-band technique can be used to screen large numbers of genotypes in the field for the presence of rapid root growth. For short season crops, rate of root growth in the first 2 months in the field should be a good predictor of final extensiveness and depth of rooting.
SIVAKUMAR -cropsci2015.03.0139.pdf
1 ReseaRch I ncreasing yield potential per se still remains a major objective of crop improvement programs worldwide . A significant proportion of the yield potential of CIMMYT's semidwarf spring wheat lines can be explained by genetic variability for adaptation to agronomic planting density . Earlier-released lower yielding lines showed a higher yield response to reduction in interplant competition-treatments that increased light penetration to the lower canopy from boot stage onward, as well as treatments that combined increased light penetration with decreased belowground competition-than modern higher yielding varieties. The results indicated the sensitivity of low-yielding genotypes to plant density and the potential of some high-yielding genotypes to perform well both under high interplant competition and reduced interplant competition. In other words, high-yield-potential (HYP) genotypes respond less when interplant competition was reduced than the earlier-released low-yield-potential (LYP) lines.
Root hairs and phosphorus acquisition of wheat and barley cultivars
Plant and Soil, 1997
Root-soil contact is an important factor for uptake of a less mobile soil nutrient such as phosphorus (P) by crop plants. Root hairs can substantially increase root-soil contact. Identification of crop cultivars with more and longer root hairs can, therefore, be useful for increasing P uptake in low input agriculture. We studied the root hairs of wheat (Triticum aestivum L. cvs. Kosack, Foreman, Kraka) and barley cultivars (Hordeum vulgare L. cvs. Angora, Hamu, Alexis, Canut) in relation to P depletion from the rhizosphere in three soils of different P levels (0.45, 1.1 and 1.6 mmoles P kg ,1 soil; extracted with 0.5 M NaHCO 3 ). Root hairs were measured in solution culture having nutrients and concentration similar to soil solution. Root hairs of Kraka were much longer (1.27 0.26 mm) and denser (38 3) hairs mm ,1 root) than those of Kosack which had shorter (0.49 0.2 mm) and fewer hairs mm ,1 root) root hairs. Root hairs increased root surface area (RSA) of Kraka by 341%. The increase with Foreman was 142% and with Kosack it was 95%. For winter barley, the length (1.1 0.3 mm) and density (30 1 hairs mm ,1 root) of root hairs of Hamu differed from root hair length (0.52 0.18 mm) and density (27 1 hairs mm ,1 root) of Angora. Root hairs of spring barley cultivars differed in length (Canut 1.0 0.24 mm; Alexis 0.64 0.19 mm) but not in density (Canut 31 1, Alexis 30 2 hairs mm ,1 root). Root hair diameter did not differ among the cultivars. Root hairs increased RSA of Canut by 245%, Hamu by 237%, Alexis by 143% and Angora 112%. The variation in root hair parameters of the cultivars was related to quantity of P depleted from rhizosphere. The correlation (R 2 ) between the root hair lengths of wheat cultivars and the quantity of P depleted from the rhizosphere soil (Q) was (0.99 ) in low-P, (0.85 ) in medium-P and (0.78 ) in high-P soil. The values of (R 2 ) between the root hair surface areas of wheat cultivars and Q were (1.00 ) in low-P, (0.74 ) in medium-P and (0.66 ) in high-P soil. Similar high values of R 2 were found for barley. These results show that the variation in root hairs of cereal cultivars can be considerable and it can play a significant role in P acquisition, especially in low-P soils.
Field Crops Research, 2008
Root lodging is an important adversity affecting sunflower (Helianthus annuus L.) production in Argentina under current husbandry practices, and may limit progress towards the achievement of higher yields via increased plant population density. Although there are perceptions that lodging susceptibility varies across developmental stages, crop population densities, genotypes and soil types, these perceptions have not been tested for sunflower using a standardized experimental protocol. This study aimed at: (1) identifying the sources of the variation in root lodging susceptibility in response to variations in crop population density in two genotypes of reputedly different susceptibility; (2) detecting the crop developmental stages most susceptible to root lodging; and (3) examining the relationships between root failure moment, root plate diameter and soil shear strength. We mechanically induced lodging at three developmental stages in plants rooted in pre-wetted plots. The crops were grown at 5.6 plants m À2 over 3 years on either Typic Argiudoll or Typic Hapludoll soils and at 3, 5.6, 10 and 16 plants m À2 on a Typic Argiudoll. The force needed to induce root lodging (root failure moment) and root plate diameter varied across genotypes, plant densities and developmental stages. Root failure moment and root plate diameters were greater ( p < 0.05 for both variables) in the resistant hybrid across the three development stages and almost all crop population densities. For both hybrids, the most susceptible development stage was R2, and root failure moment and root plate diameter diminished ( p < 0.05) as crop population density increased. Although root failure moment did not differ between soil types, root plate diameter was greater ( p < 0.0001) in the coarser soil. The relationship between root failure moment and the product of root plate diameter cubed by soil shear strength (a measure of plant anchorage strength) for both hybrids, both soil types, and all crop population densities could be described by a single linear relationship (y = 0.2382x; R 2 = 0.812; p < 0.025).
Novel QTLs for growth angle of seminal roots in wheat (Triticum aestivum L.)
Plant and Soil, 2011
Aims Because plants cannot change their environmental circumstances by changing their location, they must instead adapt to a wide variety of environmental conditions, especially soil conditions. One of the most effective ways for a plant to adapt to a given soil condition is by modifying its root system architecture. We aim to identify the genetic factors controlling root growth angle, a trait that affects root system architecture. Methods The present study consisted of a genetic analysis of the seminal root growth angle in wheat; the parental varieties of the doubled haploid lines (DHLs) used in this study exhibited significantly different root growth directions. Using the 'basket' method, the ratio of deep roots (DRR; the proportion of total roots with GA > 45 degrees) was observed for evaluating deep rooting. Results We were able to identify novel quantitative trait loci (QTLs) controlling the gravitropic and hydrotropic responses of wheat roots. Moreover, we detected one QTL for seminal root number per seedling (RN) on chromosome 5A and two QTLs for seminal root elongation rate (ER) on chromosomes 5D and 7D. Conclusions Gravitropic and hydrotropic responses of wheat roots, which play a significant role in establishing root system architecture, are controlled by independent genetic factors.
Genome, 2000
Drought is the major abiotic stress limiting rice (Oryza sativa) production and yield stability in rainfed lowland and upland ecosystems. Root systems play an important role in drought resistance. Incorporation of root selection criteria in drought resistance improvement is difficult due to lack of reliable and efficient screening techniques. Using a wax-petrolatum layer system simulated to compacted soil layers, root traits were evaluated in a doubled haploid (DH) population derived from the cross between 'IR64' and 'Azucena'. Twelve putative QTLs (quantitative trait loci) were detected by interval mapping comprising four QTLs for root-penetration ability, four QTLs for root thickness, two QTLs for penetrated root number, and two QTLs for total root number. These QTLs individually explained 8.4% to 16.4% of the phenotypic variation. No QTL was detected for maximum penetrated root length by interval mapping. One QTL located between RG104 and RG348 was found to influence both root-penetration ability and root thickness. QTLs for root-penetration ability and root thickness were compared across two populations, 'IR64'-'Azucena' and 'CO39'-'Moroberekan', and different testing conditions. The identified consistent QTLs could be used for markerassisted selection for deep and thick roots with high root-penetration ability in rice.