Marker‐assisted backcross breeding for improvement of drought tolerance in bread wheat (Triticum aestivum L. em Thell)

Drought stress is presently a major productivity limiting factor in wheat. This study developed five wheat lines with inbuilt tolerance to drought stress using marker‐assisted backcross breeding (MABB) approach employing three linked quantitative trait loci (QTLs) in an initial population of 516 BC₁F₁ plants. The high‐yielding wheat cultivar ‘HD2733’ grown over last few years extensively in the eastern plains of India is largely sensitive to drought and is used as the recurrent parent. ‘HI1500’ released for water‐limiting conditions and carrying drought‐tolerant QTLs was used as donor parent. MABB lines were advanced using foreground and background selection, coupled with stringent phenotyping. We identified 29 lines that were homozygous for targeted QTLs in different combinations with background recovery range of 89.2%–95.4%. Further evaluation of selected lines for physiological traits and distinctness, uniformity and stability (DUS) characters under rainfed condition identified five potential varieties for national varietal evaluation programme in the zone. The report is first of its kind in implementing known QTLs for the development of drought‐tolerant wheat lines through MABB approach.     

甘蔗茎分枝：稀有的形态分离

虽然在甘蔗同节上出现多芽现象已被报道,但是却未曾发现同节多芽能独立生长成蔗茎的现象。文章阐述了2008～2009年度在甘蔗品种CoS 96268宿根蔗大田观察到的一株甘蔗植株上发生的独特的形态分离现象。在该株甘蔗地上部的第7、8节上均有2个芽,但第8节出现溢痕,将该节间分成不等的两部分;该分离部分在第9节间更为明显,并独立生长成两条蔗茎（分枝）,每条蔗茎均具有正常的节间形态。     

Review on Biotechnological advances in Vigna radiata and their future prospects

Journal of Crop Science and Biotechnology - Mungbean (Vigna radiata L. Wilczek) is an unique source of protein supplement with full of benefits as medicinal and climate friendly crop. Hence from...     

Mechanical and physical characterization of sodium hydroxide treated Borassus fruit fibers

In order to improve the properties by chemical modification and to optimize the alkali concentration,we treated Borassus fruit fine fibers with aqueous sodium hydroxide solutions of different concentrations.In each case,the tensile properties of the fibers were determined.The morphology of the untreated and alkali treated fibers was observed using scanning electron microscope.The surface of the fibers became rough on alkali treatment.The tensile properties of the fibers improved on alkali treatment.The fibers attained maximum tensile properties when treated with 15% aqueous sodium hydroxide solution and decreased thereafter.The crystallinity index of the fibers showed a similar trend.The thermal stability of the alkali treated fibers was found to be higher than that of untreated fibers.Further,the char content was maximum for fibers treated with alkali having concentration of 15% and above.The chemical composition indicated that the percentageof α-cellulose was maximum when the fibers were treated with 15% aqueous sodium hydroxide solution and then decreased thereafter thus indicating the beginning of degradation of the fibers at higher concentrations.Thus,the optimum concentration of NaOH was established as 15% for alkali treatment of the Borassus fibers.     

Evaluation of somaclonal variation for genetic improvement of patchouli (<Emphasis Type="Italic">Pogostemon patchouli</Emphasis>), an exclusively vegetatively propagated aromatic plant

Patchouli (Pogostemon patchouli) is an important, exclusively vegetatively propagated aromatic plant, whose essential oil is widely used in perfumery and cosmetic products. Forty SC1 generation (first generation following in vitro phase) somaclones selected randomly from about 400 somaclones developed from the variety Johore, were multiplied through stem cuttings and evaluated in SC₂ and SC₃ generations to study the extent of somaclonal variation generated for plant height, herb yield, essential oil content, essential oil yield, and seven constituents of the essential oil. Significant or highly significant somaclonal variation was observed for plant height, herb yield, essential oil content, essential oil yield, and contents of patchouli alcohol, α-guaiene, α,δ-patchoulene, and α-bulnesene in the essential oil. The number of somaclones significantly superior to the parental variety for plant height, herb yield, essential oil content, and patchouli alcohol content in the essential oil ranged from 8–16 and the maximum superiority over the parental variety for these traits ranged from 21–79%. Broad-sense heritability estimates of plant height, herb yield, and essential oil content were 0.60–0.70 while those of essential oil yield and patchouli alcohol content were 0.44 and 0.47, respectively. Heritability estimates of other studied essential oil constituents were generally low (0.12–0.38). A high positive correlation was observed between essential oil yield and herb yield suggesting that selection for herb yield would be effective in improving essential oil yield. Patchouli alcohol content in the essential oil was negatively correlated with all the studied traits. Somaclonal variation, heritabilities of traits, and inter-trait correlations are reported for the first time in patchouli.     

Raised and sunken bed technique for agroforestry on alkali soils of northwest India

Many forest tree and fruit species can be raised on highly alkali soil (pH > 10) but some of them such as pomegranate (Punica granatum) are unable to tolerate water stagnation. To avoid water stagnation problems during the monsoon the raised and sunken bed technique has been found suitable for agroforestry practices on highly alkali soil. One fruit‐yielding pomegranate and one oil‐yielding salvadora (Salvadora persica) plantation species were successfully grown on raised bunds to avoid water stagnation and rice–wheat and berseem–kallar grass rotation were grown on sunken‐beds constructed for the purpose. The experiment was initiated in 1996 and the above two crop rotations were followed for two consecutive years starting in the summer season. Results of these experiments have also shown that good growth of plantations, on an average 4·3 to 4·9 t ha⁻¹ rice (salt tolerant var. CSR‐10) and 1·2 to 1·4 t ha⁻¹ wheat (KRL 1–4), were obtained in sunken beds. In another rotation 21·3 to 36.8 t ha⁻¹ fresh forage of kallar grass (Leptochloa fusca) and 44·9 to 47·8 t ha⁻¹ fresh forage of berseem (Trifolium alexandrium) were obtained. After two years of the experiment, soil amelioration in terms of reduction in soil pH was significant. The effect of plantation in reducing soil pH showed that the pomegranate and salvadora both helped in reduction of soil pH, but the latter due to its well‐developed lateral root system was more efficient in lowering the soil pH even at lower depths. The reduction in soil pH by the berseem–kallar grass rotation was better than under rice–wheat rotation. Copyright © 2001 John Wiley & Sons, Ltd.     

Analyzing the efficiency of soil amendments and irrigation for plant production on heterogeneous sandy soils under greenhouse conditions

Variability in soil properties is a complication for fertilization, irrigation, and amendment application. However, only limited progress has been made in managing soil variability for uniform productivity and increased water‐use efficiency. This study was designed to ameliorate the poor‐productivity areas of the variable sandy soils in Florida citrus groves by using frequent small irrigations and applying organic and inorganic soil amendments. Two greenhouse experiments were set up with sorghum and radish as bioassay crops in a randomized complete block design (RCBD). The factors studied were two soil‐productivity classes (very poor and very good), two water contents (50% and 100% of field capacity), two amendments (phosphatic clay and Fe humate), and two amendment rates (10 and 25 g kg^–1 for sorghum and 50 and 100 g kg^–1 for radish). Amendments applied at 50 and 100 g kg^–1 increased the water‐holding capacity (WHC) of poor soil by 2‐ to 6‐fold, respectively. The lower rates (10 and 25 g kg^–1) of amendments were not effective in enhancing sorghum growth. The higher rates (50 and 100 g kg^–1) doubled the radish growth as compared to the control. The results indicate that rates greater than 50 g kg^–1 of both amendments were effective in improving water retention and increasing productivity. Irrigation treatment of 100% of field capacity (FC) increased the sorghum and radish growth by about 2‐fold as compared with the 50%–water content treatment. The results suggest that the root‐zone water content should be maintained near FC by frequent small irrigations to enhance water availability in excessively drained sandy soils. In addition, application of soil amendments in the root zone can enhance the water retention of these soils. Furthermore, managing variable sandy soils with WHC‐based irrigation can increase water uptake and crop production in the poor areas of the grove.     

Synergistic effect of arbuscular mycorrhizal fungi and Bacillus subtilis on the biomass and essential oil yield of rose-scented geranium (Pelargonium graveolens)

Four different arbuscular mycorrhizal (AM) fungi, Glomus aggregatum, Glomus fasciculatum, Glomus intraradices and Glomus mosseae, were used alone and in combinations with Bacillus subtilis to evaluate their capability to increase the productivity of geranium. Mycorrhizal treatment increased the growth and total biomass invariably over non-mycorrhizal control plants. In AM alone treatment, the best result was obtained for G. mosseae treatment, where 380.9 and 335.3 g fresh herb yield per pot was recorded in 2005–2006 and 2006–2007, respectively, an increase of 75.3 and 85.9% over controls. Plants inoculated with B. subtilis alone yielded 287.8 and 252.3 g fresh herb, an increase of 32.4 and 39.9% over uninoculated controls. However, B. subtilis in combination with G. mosseae produced the highest herb yield, i.e. 410.8 and 347.8 g herbs pot^?1, an increase of 89.4 and 92.9% over untreated controls. The field experimental data validated the results of the pot experiment. Treatment with G. mosseae alone increased herb yield by 49.4%, whereas in combination with B. subtilis, it increased herb yield by 59.5%. Treatment with AM fungi and B. subtilis did not affect the essential oil content of the plant, but total oil yield was significantly increased because of the increase in biomass production.     

EFFECT OF APPLIED LIME AND BORON ON THE AVAILABILITY OF NUTRIENTS IN AN ACID SOIL

Productivity of resources on acid soils occupying one fourth of the total area in India is abysmally low. Lime is applied to such soils with the primary objective of increasing the productivity of crops by enhancing the availability of native and applied plant nutrients. Greenhouse pot experiments and laboratory experiments were conducted to evaluate the effects of lime and boron (B) on the availability of nutrients in soils and their uptake by plants. The application of lime enhanced the available nitrogen (N,), phosphorus (P), calcium (Ca), magnesium (Mg), sulfur (S), and zinc (Zn) content in soils, which was reflected in their uptake by sunflower (Helianthus annus). On the contrary, availability of copper (Cu), iron (Fe), and manganese (Mn) in soil was reduced due to liming. Sunflower responded very well in terms of dry matter yield to B application to the extent of 175% and 188% under 1 and 2 mg kg^?1 applied levels of B, respectively. Dry matter yield of sunflower was reduced to the tune of 29.2 and 42.7% under 2/3 and 1 lime requirement (LR), respectively, over control. Lime application at 1/3 LR with 2 mg kg^?1 of applied B emerged as an optimum combination in acid soils.