Water relations and productivity of alfalfa populations divergently selected for leaflet size

Estill, K.; Delaney, R. H.; Ditterline, R. L.; Smith, William K.

doi:10.1016/0378-4290(93)90163-h

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…Smaller leaves generally contribute to drought resistance by reducing the water loss from shoots (Turner, 1979). However, material selected for smaller leaflet showed higher transpiration rate besides lower growth rate per unit area compared with the larger-leaflet selection in a relatively cool environment (Estill et al, 1993).…”

Section: Discussionmentioning

confidence: 99%

Diversity, genetic structure, distinctness and agronomic value of Italian lucerne (Medicago sativaL.) landraces

Annicchiarico

2006

Euphytica

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Eleven landraces belonging to the seven commercial ecotypes of northern Italy, and seven elite varieties, were evaluated with the aims of: (i) comparing landrace and variety germplasm for dry weight (DW, recorded across three harvests spanning over two years) and morphophysiological characteristics; (ii) estimating among-population (s 2 A ) and within-population (s 2 W ) genetic variances of landrace and variety germplasms; (iii) investigating the interrelationships among traits at the plant and the population levels; (iv) exploring patterns of phenotypic diversity, and the relationships between diversity and environmental variables at landrace collecting sites; and (v) assessing the distinctness of ecotypes. Some 256 or 512 genotypes per landrace, and 128 genotypes per variety, were grown in dense stand in an unreplicated design together with a replicated clone. Compared with varieties, landrace material showed higher total DW (+9%) and DW at the last harvest (+43%), lower (2.5-fold) summer mortality and autumn dormancy (P < 0.01), and similar winter mortality. Landraces exhibited a greater s 2 W value than varieties for all traits except autumn dormancy and number of florets per inflorescence (P < 0.01), with s 2 W always exceeding s 2 A (P < 0.01). The ratio of s 2 W to s 2 A averaged 23.1 for landraces and 6.5 for varieties across eight traits. Frequency of mowing at collecting sites was associated with higher total DW, better persistence, lower summer and winter mortality, larger leaflets and more stems per plant (r ≥ 0.66, P < 0.05). Cluster analysis showed that landraces geographically close or belonging to the same commercial ecotype tended to greater similarity. However, one landrace that evolved under very frequent mowing differed greatly from other landraces of the same ecotype. Based on discriminant analysis, two ecotypes may be sufficiently distinct for registration in a sui generis system, even though they may not meet the criteria for registration under a homegenity requirement.

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Section: Discussionmentioning

confidence: 99%

Diversity, genetic structure, distinctness and agronomic value of Italian lucerne (Medicago sativaL.) landraces

Annicchiarico

2006

Euphytica

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“…Collectively, our data support the hypothesis that increased tolerance to several different environmental stresses can be achieved through increased tolerance of oxidative stress. Yet, it is somewhat surprising that this positive response occurs as the consequence of the overexpression of a single transgene, especially when both genetic and physiological studies have clearly shown that tolerance to freezing (Stone et al, 1993) and to drought (Estill et al, 1993) are quantitative genetic traits that are not easily manipulated by plant breeding (Fowler et al, 1983). The observed effects of the Mn-SOD transgene on alfalfa's tolerance to freezing and water deficit and its field performance might simply be due to the increased efficiency by which superoxide is removed from the cells of the transgenic plants d u r i n g periods of stress.…”

Section: Discussionmentioning

confidence: 99%

Water-Deficit Tolerance and Field Performance of Transgenic Alfalfa Overexpressing Superoxide Dismutase

et al. 1996

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Transgenic alfalfa (Medicago safiva) expressing Mn-superoxide dismutase cDNA tended to have reduced injury from water-deficit stress as determined by chlorophyll fluorescence, electrolyte leakage, and regrowth from crowns. A 3-year field trial indicated that yield and survival of transgenic plants were significantly improved, supporting the hypothesis that tolerance of oxidative stress is important in adaptation to field environments.Many of the degenerative reactions associated with severa1 biotic, abiotic, and xenobiotic stresses are mediated by toxic, reactive oxygen intermediates formed from superoxide, such as the hydroxyl radical (Scandalios, 1993; Allen, 1995). These stresses include the herbicide paraquat (Bowler et al., 1991;Herouart et al., 1993), ozone (Van Camp et al., 1994), anoxia (Monk et al., 1989), pathogens (Mehdy, 1994), desiccation (Senaratna et al., 1985a(Senaratna et al., , 1985b, and freezing (Kendall and McKersie, 1989;McKersie et al., 1993). The mechanisms to detoxify oxygen radicals are varied, and the complex interactions among the antioxidants in different subcellular compartments, cells, and tissues are only now being elucidated. SOD is an essential component of these defense mechanisms because it dismutates two superoxide radicals to produce hydrogen peroxide and oxygen (Scandalios, 1993; Allen, 1995). The observation that water deficiency caused the chloroplasts of wheat (Trificum aestivum L.) to reduce oxygen to superoxide because of a drought-impaired electron transport system (Price et al., 1989) prompted us to hypothesize that plants overexpressing SOD might have improved tolerance of water deficit. Previously, an Mn-SOD cDNA from Nicotiana plumbaginifolia was introduced into alfalfa; the primary transformants and their F, transgenic progeny showed increased survival and vigor after exposure to sublethal freezing stress . We now report the results of two further experiments with these transgenic plants, indicating that manipulation of genes associated with oxidative stress tolerance can also improve survival and vigor after exposure to water deficit in controlled environments and over three winters in natural field environments. These preliminary studies indicate that a rigorous analysis of the oxidative stress response will aid in the genetic improvement of environmental stress tolerante in crop plants.

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“…The highest WUE was observed in the I5 treatment (2.50 kg m −3 ) which was irrigated at the branch stage of alfalfa and then followed by I1 treatment (2.47 kg m −3 ). In addition, results of Kuslu et al (2010) and Estill et al (1993) indicated that the DM and the WUE of alfalfa were decreased by water shortage. Thus, irrigation is a key factor to maintain and promote the WUE and productivity of artificial grassland (Potters et al, 2007).…”

Section: Discussionmentioning

confidence: 93%

“…However, it is difficult to schedule the irrigation since it would require complex economic and environmental analysis to determine the optimal irrigation operation. Previous studies on artificial grasslands have mainly focused on the comparison of irrigation modes and WUE of alfalfa (Grimes, Wiley & Sheesley, 1992; Estill et al, 1993; Potters et al, 2007; Kuslu et al, 2010; Singh, Kundu & Bandyopadhyay, 2010). However, there is lack of information on the effects of different irrigation schedules on artificial grassland productivity, saline-sodic soil chemical property changes, and suitable water management for the western Songnen Plain, Northeast China.…”

Section: Introductionmentioning

confidence: 99%

The impact of irrigation on yield of alfalfa and soil chemical properties of saline-sodic soils

Yang

et al. 2019

PeerJ

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Background Forage production in the saline-sodic soil of the western Songnen Plain Northeast China depends on irrigation. Therefore, the water use efficiency (WUE) and soil chemical properties are key factors in the overall forage productivity in this water scarce region. Improving forage yield, WUE, and soil properties under irrigation are very important for food and ecological security in this water-deficient region. Additionally, a suitable irrigation schedule for this region is necessary. Methods A field experiment was conducted between 2015 and 2018 to evaluate the effects of irrigation on artificial grassland productivity and the changes in soil chemical properties as well as to plan a reliable irrigation schedule for the western Songnen Plain. Eight irrigation treatments were designed, which depended on the three growth stages of alfalfa. The shoot height (SH), the chlorophyll content (SPAD), the dry yield (DM), the ratio of stem to leaves (SLR), the WUE, the changes in the chemical properties of the soil, and precipitation and evaporation were investigated. Results The SH, DM, WUE, and SLR were significantly increased by irrigation (P < 0.01). However, the SPAD resulting from irrigation was not significantly higher than the SPAD of CK (no irrigation) (P < 0.05). In addition, the soil chemical properties at the depth of 0–100 cm were significantly decreased by irrigation P (0.05). For example, the soil electrical conductivity, sodium absorption ratio, and total alkalization were reduced 182–345 μS cm−1, 8.95–9.00 (mmolc/L)1/2, and 3.29–4.65 mmolc L−1 by different irrigation treatments, respectively. Finally, considering the highest WUE of I5 (irrigation at branch stage) (2.50 kg m−3), relative high DM of I5 (787.00 g m−2), the precipitation, the evaporation, the water resources, and the changes of the soil’s chemical properties, 236.50 mm of irrigation water was recommended at the branching stage of alfalfa for the western Songnen Plain, Northeast China.

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Water relations and productivity of alfalfa populations divergently selected for leaflet size

Cited by 6 publications

References 16 publications

Diversity, genetic structure, distinctness and agronomic value of Italian lucerne (Medicago sativaL.) landraces

Diversity, genetic structure, distinctness and agronomic value of Italian lucerne (Medicago sativaL.) landraces

Water-Deficit Tolerance and Field Performance of Transgenic Alfalfa Overexpressing Superoxide Dismutase

The impact of irrigation on yield of alfalfa and soil chemical properties of saline-sodic soils

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