scholarly journals Nguyen Duc Thanh∗, Nguyen Thi Kim Lien, Pham Quang Chung, Tran Quoc Trong, Le Thi Bich Thuy, and Henry Nguyen

2017 ◽  
Vol 23 (4) ◽  
pp. 323 ◽  
Author(s):  
Nguyen Duc Thanh ◽  
Nguyen Thi Kim Lien ◽  
Pham Quang Chung ◽  
Tran Quoc Trong ◽  
Le Thi Bich Thuy ◽  
...  
Keyword(s):  
Root Length ◽  
Upland Rice ◽  
Average Distance ◽  
Rice Genome ◽  
Root Traits ◽  
Root Weight ◽  
Deep Root ◽  
Maximum Root Length ◽  
Maximum Root ◽  
Drought Resistant

Upland rice grows on 19 million ha, about 15% of the world's rice plantation [2]. The production of upland rice is crucial to agricultural economy of many countries [15]. The yield of upland rice is very low with an average of about 1 t/ha. Drought is a major constraint to the productivity of upland rice. In this paper, we present the results on mapping QTLs for root traits related to drought resistance (maximum root length, root thickness, root weight to shoot and deep root weight to shoot ratios) in upland rice using a recombinant inbreed (RI) population derived from a cross between Vietnamese upland rice accessions. The first molecular linked of Vietnamese upland rice were constructed. The map consists of 239 markers (36 SSR and 203 AFLP markers) mapped to all 12 rice chromosomes. This map covered 3973.1 cM of rice genome with an average distance of 16.62 cM between the markers. Twenty three putative QTLs were detected. Among them, four QTLs for MRL, four QTLs for R/SR, four QTLs for DR/SR, two QTL for RN, two QTLs for RT, two for PH, and five QTLs for TN were recorded. There are several SSR markers such as RM250, RM270, RM263, RM242, RM221 linked to QTL regions. They could be very useful for drought resistant selection in rice. Some common QTLs for maximum root length and deep root weight to shoot ratio were observed in different genetic background (RDB09 × R2021 and IR64 × Azorean populations) and ecological locations (IRRI and Vietnam). These QTLs could be very useful for precise locating drought resistant gene(s) and marker-assisted selection.  

scholarly journals Megalobrama amblycephala grazes preferentially on Hydrilla verticillata but makes more efficient use of Vallisneria denseserrulata: implications for biological control of submerged macrophytes

2019 ◽  
pp. 30 ◽  
Author(s):  
Chunyu Yin ◽  
Zhaoxia Wang ◽  
Yu Zhao ◽  
Yiming Gao ◽  
Wei Zhen ◽  
...  
Keyword(s):  
Submerged Macrophytes ◽  
Hydrilla Verticillata ◽  
Megalobrama Amblycephala ◽  
Food Utilization ◽  
Root Weight ◽  
Fresh Weight ◽  
Blade Width ◽  
Negative Effect ◽  
Maximum Root Length ◽  
Maximum Root

Growth of the meadow-forming macrophyte Vallisneria denseserrulata is often negatively impacted as result of shading by the canopy-forming Hydrilla verticillata. Grazing by the herbivorous cyprinid Megalobrama amblycephala is thought to control H. verticillata. We hypothesized that M. amblycephala would prefer H. verticillata over V. denseserrulata, and that where the latter is grazed, its growth will not be wholly compromised, due in part to the efficiency with which it is metabolized by the grazer. In a pond experiment, macrophytes were planted with monocultures of H. verticillata and V. denseserrulata, and in mixed cultures of the two species, with and without grazing by M. amblycephala. The results showed that in the absence of fish, the growth rate of V. denseserrulata was significantly reduced in the presence of H. verticillata. In the mixture, M. amblycephala had a significant negative effect on the growth of H. verticillata but not on V. denseserrulata. Grazing was associated with reductions in plant height, plant fresh weight and leaf fresh weight but the leaf number, maximum root length, maximum blade width, root weight and stem weight in V. denseserrulata increased. The food utilization ratio of M. amblycephala was significantly higher when grazing solely on V. denseserrulata than when grazing on H. verticillata or the mixture. Our results imply that V. denseserrulata is protected from overgrazing by the ability of M. amblycephala to make more effective metabolic use of ingested material than for H. verticillata. Furthermore, M. amblycephala is beneficial to V. denseserrulata in reducing competition from H. verticillata.

Effects of Prodiamine on Tall Fescue (Festuca arundinacea) Rooting

1995 ◽  
Vol 9 (4) ◽  
pp. 736-740
Author(s):  
Sangwook Han ◽  
Thomas W. Fermanian ◽  
Thomas B. Voigt
Keyword(s):  
Tall Fescue ◽  
Root Length ◽  
Dry Weight ◽  
Kentucky Bluegrass ◽  
Individual Response ◽  
Root Dry Weight ◽  
Significant Difference ◽  
Maximum Root Length ◽  
Maximum Root ◽  
The Mean

With the increased development of new tall fescue cultivars used in turf, it is important to understand their individual response to herbicide treatment. The effect of prodiamine on tall fescue root dry weight and root length of selected tall fescue cultivars was studied in the greenhouse in 1.3-m-deep pots of calcined clay. Prodiamine at 0.8 kg ai/ha did not significantly affect either root dry weight or root length. However, the mean root dry weight and maximum root length averaged over all cultivars were significantly reduced at 4 wk after treatment with 1.7 kg/ha. When the prodiamine treatments were repeated in a second experiment, both rates caused a significant reduction in the mean root dry weight and maximum root length but there was no significant difference between prodiamine rates. Single degree of freedom contrasts between the untreated and treated turfs for each cultivar had some differential response in root dry weight. The reduction in root dry weight in the prodiamine treatments was more pronounced in the second study because the turf was less mature. ‘Olympic’ and ‘Rebel’ tall fescue had significantly reduced root dry weight at the 1.7 kg/ha rate in first study; whereas, ‘Amigo,’ Olympic, ‘Sundance,’ and ‘Taurus' tall fescue had significant reduction in root dry weight at both 0.8 and 1.7 kg/ha prodiamine rates. ‘Midnight’ Kentucky bluegrass had significantly reduced root length at both prodiamine rates in the second experiment but in general there was little difference among tall fescue cultivars treated with prodiamine.

scholarly journals Novel approaches to improving growth of pasture legumes at low phosphorus levels

2014 ◽  
Vol 76 ◽  
pp. 197-202
Author(s):  
S.N. Nichols ◽  
J.R. Crush
Keyword(s):  
White Clover ◽  
Root Length ◽  
Specific Root Length ◽  
Root Traits ◽  
Dry Weight ◽  
Root Weight ◽  
Soil P ◽  
P Acquisition ◽  
Shoot Dry Weight ◽  
Use Efficiency

Abstract Strategies to reduce the economic and environmental costs of phosphate (P) fertiliser use in mixed pastures through plant breeding are focussed on inefficiencies in the legume component. One approach is breeding within white clover for root systems with improved P acquisition properties. Selection for root length per unit root weight (specific root length, SRL) showed that higher SRL plants could retain more biomass in the above ground fraction with decreasing soil P, whereas plants with lower SRL diverted more biomass to roots. Back cross 1 (BC1) generation interspecific hybrids between white clover and a wild relative, Trifolium uniflorum L., may possess additional root traits influencing P acquisition. In glasshouse experiments, some T. repens × T. uniflorum hybrids, back-crossed to white clover, also exhibited higher shoot dry weight than their white clover cultivar parents at low nutrient supply levels and low to intermediate soil Olsen P. This, combined with low internal P concentrations, suggests some BC1 hybrids may be more tolerant of low soil P than white clover. Differences in both P acquisition ability and internal P use efficiency may contribute to the observed yield differences. There are good prospects for delivery of new-generation clover cultivars with improved phosphate use efficiency to New Zealand farmers. Keywords: phosphorus, white clover, Trifolium uniflorum, interspecific

Phenotyping of traits imparting drought tolerance in lentil

2012 ◽  
Vol 63 (6) ◽  
pp. 547 ◽  
Author(s):  
J. Kumar ◽  
P. S. Basu ◽  
E. Srivastava ◽  
S. K. Chaturvedi ◽  
N. Nadarajan ◽  
...  
Keyword(s):  
Seed Yield ◽  
Root Length ◽  
Selection Criterion ◽  
Root Traits ◽  
Moisture Stress ◽  
Root Weight ◽  
Seedling Vigour ◽  
Breeding Lines ◽  
Spad Value ◽  
Rainfed Conditions

Lentil is one of most important pulse crops in South Asia, and invariably encounters terminal moisture stress, leading to forced maturity and lower yield. A long and prolific root system is known to enhance capacity of the plant to extract water from the lower soil strata and thus help avoid the water stress. We assessed genetic variation for 12 traits among 43 lentil genotypes comprising improved varieties and promising breeding lines. The average root length at the 65-day plant stage ranged from 42 to 83 cm. Two genotypes (EC 208362 and VKS 16/11) with shorter root length and poor dry root weight (DRW) and three genotypes (DPL 53, JL 1, and IPL 98/193) with longer root length and high DRW were identified with stable performance over the years. Relationship of root traits with seed yield under rainfed conditions was non-significant in our study. The SPAD value (chlorophyll content) showed significantly positive correlation with DRW (r = 0.45**) and root length (r = 0.44**) and thus can be used as selection criterion for phenotyping root traits which are otherwise difficult to measure in the field. In drought-prone environments, early flowering and maturity, seedling vigour, and high SPAD value, biological yield, and harvest index were identified as key traits for higher seed yield in lentil. Our results revealed significant genetic variability for these traits in lentil germplasm. Indian genotypes adapted to rainfed conditions were shown to have longer roots and higher DRW. The three genotypes (DPL 53, JL 1, and IPL 98/193) identified with superior root traits either originated from or have in their ancestries at least one parent adapted to rainfed conditions. These genotypes can be utilised for the development of mapping populations to identify QTLs associated with these traits for marker-assisted breeding of drought-tolerant, high-yielding varieties of lentil.

scholarly journals Effect of indigenous beneficial rhizobacterial isolates on growth of Litchi seedlings

2020 ◽  
Vol 26 (2) ◽  
Author(s):  
Nandini Kumari ◽  
Pushpanjali Khare
Keyword(s):  
Root Length ◽  
Germination Rate ◽  
Shoot Length ◽  
Equal Proportion ◽  
Shoot Height ◽  
Early Germination ◽  
Maximum Root Length ◽  
Number Of Leaves ◽  
Maximum Root ◽  
And Control

A pot experiment was conducted to observe the effect of indigenous strains of rhizobacteria isolated from litchi orchards of East Champaran, Bihar (India) on the growth and survivability of litchi seedlings. Three efficient native rhizobacterial isolates belonging to genera Pseudomonas, Azotobacter and Ochrobactrum were used in seven different combinations and their effect on germination rate, shoot height, root length, number of leaves were observed and recorded in litchi seedlings. Pot 7 containing mixed combination of all the three isolates in equal proportion showed maximum root length (11.7 cm) and shoot length (12.5 cm), early germination as compared to control Pot P8 devoid of any isolates. Pot 4 (Pseudomonas + Azotobacter) and pot 5 (Pseudomonas + Ochrobactrum) also gave satisfactory result in all the parameters recorded. The results clearly state that, mixture of all the three rhizobacterial isolates as “Biomix” produced stimulatory growth results on litchi seedlings as compared to sole application and control. This “Biomix” could be used for formulating effective biofertilizers for litchi orchards in future.

scholarly journals Sorghum Drought Tolerance is Associated with Deeper Root System and Decreased Transpiration Rate

2021 ◽  
Author(s):  
Srinivasan Gowsiga ◽  
Maduraimuthu Djanaguiraman ◽  
Nallasamy Thavaprakaash ◽  
Prabhakaran Jeyakumar ◽  
Govindaraj Mahalingam
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Root System ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Root Length ◽  
Total Root Length ◽  
Maximum Root Length ◽  
Maximum Root ◽  
Root And Shoot Traits

Drought decreases grain yield of sorghum [Sorghum bicolor (L.) Moench], and understanding the mechanism(s) related to drought tolerance is critical for sustaining sorghum production. Variation in root and shoot traits associated with drought tolerance were analyzed to provide an integrated view of factors that underlie the drought tolerance of sorghum. The plants were grown in the root column up to the five-leaf stage, then exposed to either 0.9 fraction of transpirable soil water (FTSW) or 0.4 FTSW for five days. In another experiment, at the five-leaf stage, stress was imposed for 14 days. Various root and shoot traits associated with drought tolerance were recorded. The seminal root angle of IS13540 was lower (24.4) than IS23143 (42.6). Drought stress increased the maximum root length (40%) and total root length (58%) of IS13540 than its irrigated control. In contrast, the maximum root length and total root length were decreased in IS23143. Similarly, across the lines, drought stress decreased stomatal conductance (37%), transpiration rate (42%), photosynthetic rate (40%), photosystem II quantum yield (20%), photochemical quenching (44%), and total dry matter production (34%) than irrigated control. An increased transpiration rate was observed in IS23143 than IS13540 under irrigated and drought stress. In IS23143, the reduction in photosynthetic rate under drought may be a combination of stomatal and non-stomatal factors. However, in IS13540, the reduction is especially by the stomatal factors. It is evident that IS13540 is a drought-tolerant line, and tolerance is related to a deep prolific root system and reduced tran-spiration rate.

scholarly journals Intraspecific genetic variation within and between improved cultivars and landraces of durum wheat in germination and root architectural traits under saline conditions

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Nidal Odat
Keyword(s):  
Genetic Variation ◽  
Durum Wheat ◽  
Root Length ◽  
Root Traits ◽  
Germination Percentage ◽  
Seminal Root ◽  
Coleoptile Length ◽  
Maximum Root ◽  
Intraspecific Genetic Variation ◽  
Architectural Traits

This study was conducted to investigate the genetic variation within and between two subgroups of durum wheat in Jordan, i.e., cultivars and landraces, in germination and root architectural traits at three salinity concentrations (50, 100 and 150 mM NaCl). The results indicate that salinity significantly impacted most traits investigated. A multivariate discriminant analysis (DA) revealed large variations (~85%) between genotypes, with significant ranking in maximum root length, total root length, seminal root length, coleoptile length, germination percentage, and total and seminal root number over the three salinities. Within the cultivar subgroup, salinity significantly influenced the germination percentage and most root traits of durum genotypes, with variable magnitudes depending on NaCl concentration and within-variety intraspecific genetic variation (ANOVAs; P < 0.05). However, within the landrace subgroup, only a salinity of 150 mM NaCl significantly affected the studied traits, and the effect of salinity on germination percentage was highly genotype dependent. Additionally, the durum genotypes in the landrace subgroup were more affected by salinity and showed more genetic variation than those in the cultivar subgroup. 

scholarly journals Identification of Markers for Root Traits Related to Drought Tolerance Using Traditional Rice Germplasm

2021 ◽  
Author(s):  
Harendra Verma ◽  
R. N. Sarma
Keyword(s):  
Drought Tolerance ◽  
Root System ◽  
Root Length ◽  
Complex Traits ◽  
Genome Wide Association Study ◽  
Root Traits ◽  
Coefficient Of Determination ◽  
Root Weight ◽  
Shoot Weight ◽  
Root And Shoot Traits

Abstract Background: Drought is one of the important constraints affecting rice productivity worldwide. The vigorous shoot and deep root system help to improve drought resistance. In present era, genome-wide association study (GWAS) is the preferred method for mapping of QTLs for complex traits such as root and drought tolerance traits. In the present study, 114 rice genotypes were evaluated for various root and shoot traits under water stress conditions. All the genotypes were genotyped using 65 SSR markers covering all 12 chromosomes for the identification of various QTLs for root and shoot traits using MLM (Q+K) model in GWAS. Results: All genotypes showed a significant amount of variation for various root and shoot traits. Correlation analysis revealed that high dry shoot weight and fresh shoot weight is associated with root length, root volume, fresh root weight and dry root weight. A total of 11 significant marker-trait associations were detected for various root, shoot and drought tolerance traits with the coefficient of determination (R2) ranging from 18.99% to 53.41%. Marker RM252 and RM212 showed association with three root traits which suggests their scope for improvement of root system in rice improvement breeding programmes. In the present study a novel QTL was detected for root length associated with RM127, explaining 19.30% of variation. Conclusion: The marker alleles with increasing phenotypic effects for root and drought-tolerant traits can be exploited for improvement of root and drought tolerance traits using marker-assisted selection.

Root traits and δ13C and δ18O of durum wheat under different water regimes

2012 ◽  
Vol 39 (5) ◽  
pp. 379 ◽  
Author(s):  
Abdelhalim Elazab ◽  
Gemma Molero ◽  
Maria Dolores Serret ◽  
José Luis Araus
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Durum Wheat ◽  
Root Length ◽  
Recombinant Inbred Lines ◽  
Flag Leaf ◽  
Root Traits ◽  
Root Weight ◽  
Genotypic Differences ◽  
Δ13c And Δ18o

Plant growth, root characteristics and the stable carbon (δ13C) and oxygen (δ18O) composition were studied in durum wheat. Four recombinant inbred lines with good agronomic adaptation were grown under well watered (WW) and water stress (WS) conditions until mid-grain filling in lysimeters. Gas exchange was measured in the flag leaf just before harvest and then the aerial dry matter (Aerial DM), root weight density (RWD) and root length density (RLD) and the specific root length (SRL) were evaluated and the δ13C and δ18O of the roots, the flag leaf blade and the spike were analysed. Water stress decreased stomatal conductance, plant accumulated transpiration and Aerial DM, whereas δ13C and δ18O increased. Genotypic differences were found for all gas-exchange and root traits and isotope signatures. Aerial DM was positively correlated with RLD, regardless of the water regime, whereas it was negatively correlated with δ13C and δ18O, but only under WW conditions. Moreover, RWD and RLD were negatively related to both δ13C and δ18O under the WW regime, but no clear pattern existed under WS. Our study supports the use of δ13C and δ18O as proxies for selecting root traits associated with higher growth in the absence of water stress.

scholarly journals Comparison of Early and Conventional Soybean Production Systems for Yield and other Agronomic Traits

2017 ◽  
Vol 1 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Ouertani Khaled ◽  
Evandrew Washington ◽  
Patricia Lage ◽  
Stella K. Kantartzi ◽  
David A. Lightfoot ◽  
...  
Keyword(s):  
Root Length ◽  
Lateral Root ◽  
Dry Weight ◽  
Fresh Weight ◽  
Soybean Production ◽  
Shoot Fresh Weight ◽  
Root Dry Weight ◽  
Shoot Dry Weight ◽  
Maximum Root Length ◽  
Maximum Root

The early soybean production system (ESPS) was reported to be beneficial for yield compared to the conventional soybean production system (CSPS) and is widely used in the Southern USA. The objective of this study was to compare yield, yield components, root traits, and shoot traits in ESPS (April planting) and CSPS (June planting) in NC Sandhills using a recombinant inbred line (RIL) population, ‘Hartwig’ by ‘Flyer’ (n=92). The population was grown in Spring Lake, NC in 2008 at a density of 16 seeds m-2. The traits measured were days to germination, days to flowering, plant height, seed weight, seed number, pod number, harvest index, root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, maximum root length, and lateral root number. The survival rate ranged from 83.7 to 90.22% for ESPS; however, it was 21.74% for CSPS. Significant differences were observed for almost all traits measured in ESPS (April) compared to CSPS (June) apart from fresh root weight and lateral root number. An average increase in flowering time of 9 days was observed in CSPS compared to ESPS. On the other hand, several traits showed a significant mean decrease in CSPS compared to ESPS as plant height by 41.96%, seed weight by 74.7%, harvest index by 73.3%, pod number by 65.2%, and seed number by 64.9%. The means for root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, maximum root length, and lateral root numbers are shown in Table 2 for both ESPS and CSPS. The results indicated an average decrease of 40.4% in root fresh weight, of 70.2% in root dry weight, of 68.1% in shoot fresh weight, of 80.1% in shoot dry weight, and of 83.3% in maximum root length in CSPS compared to ESPS. However, lateral root numbers increased by an average of 12.7% in CSPS compared to ESPS. Therefore, CSPS may not be appropriate for soybean at least in NC Sandhills.

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