Semi Dwarf Research Articles

Genetic Analysis of M5 Generation of Gamma Irradiated Red Rice (Oryza sativa L.) Mutant lines

In rice, induced mutations play a significant role in development of semi dwarf and high yielding variants. The genetic variability induced by four Gamma rays treatments was studied in traditional red rice variety Kajejaya in Randomized complete block design with two replications during Kharif 2021. Analysis of variance documented Gamma rays treatment brought significant variability and exhibited a wide range of values for all traits. Six superior mutants(T35-L-06, T35-L-17, T35-L-15, T45-L-07 T45-L-13 and T45-L-06) exhibited more number of productive tillers/plant, panicle length, number of filled grains/panicle, high test weight and higher grain yield/plant and T45-L-13, T45-L-06 and T35-L-15 mutants took lesser days to mature(114,117.5 and 118 days) and exhibited reduced plant height(84, 80 and 72cm) compared to untreated parent check. Induced mutations were effective in creating variability in plant height and maturity duration along with increased mean of reproductive components at higher doses (35kR and 45kR) as compared to lower doses(15kR and 25kR).

Rice CO 53: A high yielding drought tolerant rice variety for drought prone districts of Tamil Nadu

Early duration drought tolerant rice culture CB 06803, a derivative of the cross PMK (R ) 3 x Norungan was released as Rice CO 53 during the year 2020 as an alternate variety for Anna(R)4, with 115 -120 days duration. It possesses desirable features like high yield, drought tolerance and better physiological efficiency. This culture with semi dwarf stature has efficient tillering capacity, long droopy panicles with a highly acceptable plant characters and is a replacement for the rice variety Anna (R) 4 due to its grain yield and pest and disease resistance. In the overall yield analysis, the culture CB06803 recorded an overall mean grain yield of 3718 kg/ha which was 12.19 per cent increase over TKM (R) 12 and 14.08 per cent over Anna (R) 4 under dry condition. Under semi dry condition, it recorded 3866 kg/ha with 18.40 per cent increase over TKM (R) 12 and 8.67 per cent over Anna (R) 4. It is moderately resistant to WBPH, leaf blast, neck blast, sheath rot, brown spot and RTD under artificial condition. It has white short bold rice with high milling percentage (69.6), head rice recovery (59.6%) and suitable for idly making. The culture, CB 06803 had better  agronomic efficiency than TKM (R)12 and Anna (R) 4 by recording more number of productive tillers per plant and grain yield under control and drought. The culture CB 06803 had better physiological efficiency under drought than TKM (R) 12 and Anna (R) 4  having higher RWC, total chlorophyll content, chlorophyll stability index, photosynthetic rate, stomatal conductance and photo chemical efficiency. The culture had higher proline content than TKM (R) 12 and was on par with Anna (R) 4. It had higher catalase activity than Anna (R) 4. CB 06803 had better physiological efficiency under drought by showing partial closure of stomata as that of Sahbagidhan. CO 53 with higher grain yield under drought, disease resistance and short bold grains and suitable for cultivation in drought prone districts of Tamil Nadu as direct seeded rainfed or semi dry rice ecosystem. Keywords: Rice CO 53, bold grain rice, short duration, drought tolerance

INTEGRATED PEST MANAGEMENT (IPM), BEST APPROACH TO CONTROL THE AGRICULTURALLY HARMFUL PEST POPULATION

Green revolution has no doubt led to increased global food supplies, but at the same time it has introduced several ecological, environmental, and socio-economic problems. After green revolution, using of dwarf and semi dwarf high yielding varieties of crops, increased used of Agrochemicals and irrigation happened which resulted in increased intensity of several pest. To control these pests, we opted synthetic chemicals as best method, but it created a lot of health issues and killed beneficial insects too. Residual impact of chemical has shown hazardous impact. Now it’s time to change by opting IPM practice i.e. Integrated Pest Management. IPM is not a new philosophy, the concept has been around 1920’s when cotton pest management was developed.

Features of Growth Processes of Sweet Cherry Trees of Various Ripening Terms in the Conditions of the Right-Bank Forest-Steppe of Ukraine

One of the main requirements of the new stone fruit varieties recommended for commercial cultivation is a compact crown shape that allows for greater plant density and easier crown maintenance. The aim of the research was to establish the growth processes of the above-ground parts of cherry trees in varieties of different ripening periods. The article presents the results of studies of the features of apical and lateral growth of sweet cherry trees. Biological and varietal features of tree growth strength, growth and total length of annual shoots are determined. The dependence of tree trunk growth on apical growth force is established. According to the results of research, sweet cherry varieties are grouped according to the strength of growth: the vigorous varieties are Amazonka, Dar Mliyeva, Zoryana, Mliyivska zhovta; the semi dwarf are Aboryhenka, Alyonushka, Drohana zhovta, Mirazh; the dwarfing are Biryuza, Donetskyy uholyok, Melitopolska krapchasta, Meotida. The smallest increase in trunk diameter was found for the dwarfing variety Biryuza, and the largest – for the variety Drohana zhovta. The highest yield load per unit cross-sectional area of the trunk was recorded for the variety Donetskyy uholyok, the lowest – for Drohana zhovta. The amount of growth in the trunk diameter was inversely dependent on a load of trees with the crop and the strength of apical growth of sweet cherry trees. The features of shoot-forming ability allow characterising the shape of the crown of cherry trees: round – Donetskyy uholyok, Amazonka; high-round – varieties of Aborigenka, Dar Mliyeva, Zoryana; wide-pyramidal – Alyonushka, Drohana zhovta, Melitopolska krap-chasta; pyramidal – Mliyivska zhovta, Mirazh; low – Meotida, Biryuza. Dar Mliyeva, Zoryana, Mirazh, Melitopolska krapchasta and Drohana zhovta varieties have high shootability; the Mliyivska zhovta, Aboryhenka, Meotida, Amazonka varieties have medium shootability; Alyonushka, Biryuza, Donetskyy uholyok varieties have low shootability

Effect of Establishment Methods and Nutrient Management Practices on Growth Characters and Yield of Rice (Oryza sativa L.)

Aim: Study was conducted to compare and to identify the best combination of rice crop establishment method and nutrient management in terms of crop growth, development and yield.
 Study Design: Experiment was laid out in splitplot design.
 Place and Duration of Study: The field experiments were conducted at the research farm of Indian Institute of Rice Research, Hyderabad, Telangana State, India during the kharifand rabiseasons of 2011-12 and 2012-13.
 Methodology: The treatments consisted of four establishment methods (System of rice intensification (SRI), modified drum seeder, normal drum seeder and normal transplanting) as main plot treatments and four nutrient management practices (100% recommended dosage of nitrogen (RDN) through inorganic, 75% RDN through inorganic+ 25% RDN through organic, 50% RDN through inorganic+50% RDN through organic and 100% RDN through organic) as sub plot treatments with 16 treatment combinations and three replications. The semi dwarf, high yielding Sampada variety was raised during the study period.
 Results: Growth parameters like plant height, leaf area index (LAI), dry matter accumulation, number of tillers per square meter were observed at 45,75,105 days after transplanting and at harvest stages. The two years experimental results and the pooled mean data revealed that SRI recorded significantly superior growth parameters at all the crop growth stages followed by modified drum seeder. In respect of subplots 50% RDN through inorganic+50% RDN through organic resulted in superior growth parameters and yield.
 Conclusions:The combination of SRI with nutrient management practice 50% nitrogen through urea and 50% nitrogen through vermiconpost resulted in greater growth parameters and grain yield.

NLR 3354 (Nellore Dhanyarasi): A short duration fine grain, blast tolerant rice culture for Andhra Pradesh

The culture NLR 3354 is a cross derivative of NLR 34242 x NLR 34303 which was released during 2019 by SVRC, Andhra Pradesh with 120-125 days duration, high yielding ability and better adaptability. This culture with semi dwarf stature has efficient tillering capacity, medium droopy panicles with highly acceptable plant characters and is a good replacement for the rice variety NLR 34449 due to its high grain yield and pest and disease tolerance ability. It possess tolerance to leaf and neck blast. It recorded an average yield of 6410 kg/ha over the check of 5799 kg/ha in different trials conducted for a period of 9 years. It produces good quality cooked rice besides high milling and head rice recovery. It produces medium slender white rice with intermediate amylose, soft gel consistency and moderate gelatinization temperature. It produces good quality cooked rice besides high milling and head rice recovery. Key wordsNLR 3354, short duration, rice variety  

Altitudinal and depth wise variation of physico-chemical properties, macronutrient status of soil and leaf and their correlation studies of HDP apple orchards under MM 106 rootstock of north Kashmir

Apple (Malus domestica Borkh.) one of the rosaceous group is native of Asia Minor to western Himalayas. High density apple orchards developed on semi dwarf rootstock like MM 106 have become common in many apple growing regions of the Kashmir especially North Kashmir. Suitability of soil as a medium of plant growth depends on both its physico-chemical properties and nutritional status. As per the results soils were slightly acidic to slightly alkaline and ranged statically from 6.55 to 7.52 in surface and 7.31 to 7.78 in sub-surface soils. The highest values of organic carbon in surface and sub-surface soils were found in orchards located in high altitude followed by mid and low altitudes orchard soils. The available nitrogen, phosphorus and potassium content varied significantly with altitude and the higher values were observed in HDP apple orchards located in high altitude. The available nitrogen and phosphorus showed a decreasing trend while as available potassium showed irregular with soil depth. The foliar contents of nitrogen, phosphorus and potassium in high density apple were found to be sufficient. The leaf calcium, magnesium and sulphur varied from 1.66 to 1.75, 0.27 to 0.31, and 0.20 to 0.23 per cent respectively. Significantly higher average yield was recorded in high and mid altitudes than low altitude HDP apple orchards. Nutrients showed positive relation with organic carbon. Plants absorb nutrients from both surface as well as sub-surface soils. The present study though first of its kind on high density apple orchards is expected to be quite useful for horticulturists for formulation of future research programme.

Protocol optimization for rapid and efficient callus induction and in-vitro regeneration in rice (Oryza sativa L.) cv. CO 51

CO 51 is a recently developed semi dwarf, short duration variety of rice popularly grown in Tamil Nadu. Optimization of tissue culture protocol for the variety was one of the most important steps required; in order to make the variety suitable for genetic transformation and gene editing techniques. Immature embryos of CO 51 have been used as explant for callus induction. The immature embryos were cultured on callus induction media (NB media) containing Naphthalene Acetic Acid (NAA) 1 mg l-1, 6-Benzylaminopurine (6-BA) 1 mg l-1 and various concentrations of 2,4 Dichlorophenoxy acetic acid (2,4-D). NB media supplemented with 2.5 mg l-1of 2,4-D have been found to show the highest callus induction frequency that is 94.4%. The calli showing desired features were transferred from NB media to pre-regeneration media (NB-PR) having 2,4-D (2 mg l-1), 6-BA (1 mg l-1 ), NAA (1 mg l-1) where the calli tuned goldenyellow. These calli were then transferred to regeneration media (RNM media) supplemented with 6-BA (3 mg l-1) along with various concentrations of NAA. RNM media with1 mg l-1 NAA showed the highest frequency of shoot induction that is 72.2% with an average of 12 shoots per callus.

Re-evaluation of the rice ‘Green Revolution’ gene: the weak allele SD1-EQ from japonica rice may be beneficial for super indica rice breeding in the post-Green Revolution era

The Green Revolution of the 1960s introduced semi-dwarf cultivars of rice that had reduced lodging and increased harvest indexes. The mutant allele of Semi Dwarf 1 (SD1) is the gene underlying the Green Revolution advances in rice yield. Since that time, most of the commercial semi-dwarf cultivars carry a mutation in SD1. Unlike japonica rice cultivars containing weak functional SD1 alleles, indica rice cultivars owed their diminished stature to a null mutation in SD1. It has been proposed recently that increasing plant height and subsequently plant biomass will increase grain production in semi-dwarf cultivars used in super rice breeding programs. In this study, we evaluated the potential benefit of the weak functional allele of SD1 from japonica rice on yield improvement in the indica rice background. We found that the Green Revolution gene SD1 has pleiotropic effects on tiller number and spikelets per panicle, in addition to plant height in rice. The introduction of the weak allele SD1-EQ from the japonica cultivar ‘Nipponbare (Np)’ led not only to a substantial increase in plant height but also to an increase in yield per plant in the indica cultivar ‘9311’. This result was further confirmed in CRISPR/Cas9-mediated knockout mutants. In addition, heterosis for yield-related traits was detected at the SD1 locus, and SD1-EQ exhibited a potential improved yield in hybrid rice lines. This study provides evidence that the weak functional SD1 allele from japonica rice cultivar ‘Np’, SD1-EQ, is an excellent genetic resource for the improvement of indica rice lines with null alleles of SD1, in the post-Green Revolution era.

Domestication-driven changes in plant traits associated with changes in the assembly of the rhizosphere microbiota in tetraploid wheat

Despite the large morphological and physiological changes that plants have undergone through domestication, little is known about their impact on their microbiome. Here we characterized rhizospheric bacterial and fungal communities as well as the abundance of N-cycling microbial guilds across thirty-nine accessions of tetraploid wheat, Triticum turgidum, from four domestication groups ranging from the wild subspecies to the semi dwarf elite cultivars. We identified several microbial phylotypes displaying significant variation in their relative abundance depending on the wheat domestication group with a stronger impact of domestication on fungi. The relative abundance of potential fungal plant pathogens belonging to the Sordariomycetes class decreased in domesticated compared to wild emmer while the opposite was found for members of the Glomeromycetes, which are obligate plant symbionts. The depletion of nitrifiers and of arbuscular mycorrhizal fungi in elite wheat cultivars compared to primitive domesticated forms suggests that the Green Revolution has decreased the coupling between plant and rhizosphere microbes that are potentially important for plant nutrient availability. Both plant diameter and fine root percentage exhibited the highest number of associations with microbial taxa, highlighting their putative role in shaping the rhizosphere microbiota during domestication. Aside from domestication, significant variation of bacterial and fungal community composition was found among accessions within each domestication group. In particular, the relative abundances of Ophiostomataceae and of Rhizobiales were strongly dependent on the host accession, with heritability estimates of ~ 27% and ~ 25%, indicating that there might be room for genetic improvement via introgression of ancestral plant rhizosphere-beneficial microbe associations.

<i>Zamioculcas zamiifolia</i> novel plants with dwarf features and variegated leaves induced by colchicine

Zamioculcas zamiifolia (Lodd.) Engl. is an export-oriented, potted foliage plant used for indoor scaping. Since it shows high environmental and pest tolerability, it does not need much attention in cultivation. Thus, the aim of present study was to develop stable, novel mutants of Z. zamiifolia induced by colchicine (a mutagenic chemical) treatment. Three leaflet types (rooted leaflets with tuber, tuber initiating leaflets without roots and freshly harvested leaflets) were applied separately with four concentrations of colchicine ranging from 0 to 0.4% to induce mutations in a 70% shaded greenhouse. The experiment was conducted for three generations. Results showed that at 0.4% and 0.04% colchicine, plant size decreased in some leaflets, thus producing extreme dwarf and semi dwarf plants, respectively, which are suitable to be used as table-top, miniature ornamental plants. Some leaflets at 0.004% colchicine produced yellow and light green variegated leaflets. According to our knowledge, this is the first report of producing Z. zamiifolia plants with variegated leaves using colchicine. Other than molecular breeding, which is costly and takes a longer period, conventional breeding cannot be employed to generate new plants, since there is only one species under this genus. As such, use of chemical mutagens such as colchicine would provide a rapid means of developing new plant types of this species with attractive morphological features since there is a very narrow range of variants available in the world.

Molecular Cytogenetic Analysis and Meiotic Pairing Behavior of Progenies Originating from a Hexaploid Triticale (×Triticosecale, Wittmack) and Bread Wheat (Triticum aestivum, L.) Cross

The chromosomal constitution of 9 dwarf (D) and 8 semidwarf (SD) lines derived by crossing hexaploid Triticale line NA-75 (AABBRR, 2n = 6x = 42) with Triticumaestivum (AABBDD, 2n = 6x = 42) cv. Chinese Spring was investigated using molecular cytogenetic techniques: fluorescence in situ hybridization and genomic in situ hybridization. A wheat-rye translocation (T4DS.7RL), 8 substitution lines, and a ditelosomic addition line (7RSdt) were identified. In the substitution lines, 1, 2, or 4 pairs of wheat chromosomes, belonging to the A, B, or D genome, were replaced by rye chromosomes. Substitutions between chromosomes belonging to different wheat genomes [5B(5A), 1D(1B)] also occurred. The lines were genetically stable, each carrying 42 chromosomes, except the wheat-rye ditelosomic addition line, which carried 21 pairs of wheat chromosomes and 1 pair of rye telocentric chromosomes (7RS). The chromosome pairing behavior of the lines was studied during metaphase I of meiosis. The chromosome pairing level and the number of ring bivalents were different for each line. Besides rod bivalents, univalent and multivalent associations (tri- and quadrivalents) were also detected. The main goal of the experiment was to develop genetically stable wheat/Triticale recombinant lines carrying chromosomes/chromatin fragments originating from the R genome of Triticale line NA-75. Introgression of rye genes into hexaploid wheat can broaden its genetic diversity, and the newly developed lines can be used in wheat breeding programs.

İleri Kademe Ekmeklik Buğday (Triticum aestivum L.) Mutant Hatlarının Verim ve Kalite Parametrelerine Göre Seleksiyonu

In the presented research, conventional gamma ray mutagenesis was used to develop new mutant line(s), which have such characters moderate and/or high yielding, semi dwarf and early maturing. Thus, Selimiye cultivar, TCI2066 and three sisters’ line of TCI2021 were irradiated with 200 Gy gamma rays and segregated up to sixth generations. 15 advanced mutant lines from M6 generation and their parent and five commercial wheat cultivars, which have superior characters than others were evaluated according to some agronomic parameters, such as grain yield (GY), thousand kernel weight (TKW), test weight (TW), protein content (PRT), hardness (HARD), days of heading and plant height, under field condition during 2012-2014 growing years in Edirne, Turkey. As a result of study, the highest grain yield was determined from the mutant lines derived from Selimiye wheat cultivar than commercial cultivars. The mutant lines of TCI2021-21M4-2 and TCI2021-23M5-2 were given the highest value in terms of protein content, and the highest hardness values were determined from the mutant lines of TCI2066-9M2-3, TCI2066-9M2-1 and TCI2021-21M4-2, respectively. The mutant line of TCI2021-12M3-8 was measured the shortest one among them. Additionally, a strong positive correlation was determined between GY and TKW, and TW in both growing season. In conclusion, gamma ray mutagenesis had efficiently used in local bread wheat improving programmes to develop mutant lines with superior characters, and TKW and TW could be used as selection criteria for maintaining grain yield under divers rainfall conditions of Trakya Region.

Agrobiological evaluation of new apple clonal rootstocks of the Michurinsk State Agrarian University selection using different breeding methods

The results of many years of research on propagation of promising forms of clonal stocks of apple trees of the Michurinsk State Agrarian University selection in the mother plantation by stooling, by herbaceous cuttings and by clonal micropropagation are presented. According to the complex of economic and biological features, promising clonal rootstocks of an apple tree with high shoot-forming capacity in the mother plant were identified: dwarf apple trees 2-3-49, 2-15-2, 2-15-15, 3-4-7, 5-21-27; semi dwarf apple trees 2-3-14, 2-9-49, 2-9-102, 2-12-10, 5-24-1, 5-27-1. The rootstocks that are promising for propagation by herbaceous cuttings – 2-3-14, 2-3-49, 2-12-10, 2-15-15, 3-4-7, 5-21-93; at the same time, treatment with exogenous promoters such as IBA and NAA at a concentration of 50 mg/l increases the yield and quality of stock material. A modified MSO nutrient medium with the addition of 0.5-1.0 mg/l of 6-BAP and 0.1-0.2 mg/l of IBA is selected for the clonal micropropagation of apple stocks.

Integrating marker-assisted selection and doubled haploidy for rapid introgression of semi-dwarfing and blast resistance genes into a Basmati rice variety ‘Ranbir Basmati’

Ranbir Basmati, an early maturing pure line selection of traditional Basmati 370, is widely cultivated Basmati variety in the Indian state of Jammu and Kashmir. The variety is tall statured, prone to lodging and highly susceptible to rice blast. The present study was carried out for genetic improvement of Ranbir Basmati for semi dwarf stature and resistance to blast by introgressing semi-dwarfing gene, sd1, and blast resistance gene, Pi9 from an improved Basmati rice variety, Pusa Basmati 1637 (PB 1637).The selfed progenies of two superior BC2F1 recombinants of the cross Ranbir Basmati/PB 1637 showing maximum recovery of recurrent parent genome and phenome were analyzed with gene-based markers to select plants homozygous for both Pi9 and sd1. These plants were processed via anther culture to produce homozygous doubled haploid (DH) lines. All the anther culture derived DH plants were short-statured compared to Ranbir Basmati and exhibited high level of resistance to blast. The analysis of yield and its component traits revealed the presence of superior transgressive segregants for various traits namely, effective tillers, grains per panicle and yield per plant. Combined use of marker-assisted selection and anther culture ensured speedy conversion of Ranbir Basmati into semi-dwarf genotypes with in-built resistance to rice blast. The study demonstrated the utility of anther culture as an adjunct to marker-assisted backcross breeding schemes for instant elimination of the residual background heterozygosity of the selected recombinants.

Management of nitrogen fertilization to balance reducing lodging risk and increasing yield and protein content in spring wheat

Crop lodging (stem and root lodging) is one of the main constraints limiting grain yield and quality in spring wheat production, especially under high–yielding conditions. Few studies have been conducted to clarify the trade–off between grain yield and lodging resistance, and assess whether it is possible to manage lodging risk without a yield reduction penalty. Developing appropriate nitrogen (N) fertilizer management strategies for driving grain yield/quality while reducing (or at least not increasing) the risk of lodging is needed to achieve this. The risks of stem and root lodging were quantified by “safety factor” (SF) indicator, which represents the number of times a support organ can bear the self–weight moment of the organ that it is supporting. Two varieties with contrasting stature (tall vs. semi–dwarf), were tested under different timing and rates of N application strategies. The advantage of split–N (preplant plus top–dress application at the jointing stage) over equivalent preplant–only N application was not evidenced on yield, but grain protein (%) was improved by up to 7.5% without a yield penalty. The risk of lodging was increased with increasing N rates from zero to the highest N treatment, as indicated by decreasing stem safety factor SFs (–23.7%) and root safety factor SFr (–32.2%) across both years, and increasing visual lodging score (by 7–fold) in 2017. The split–N treatment N50 + 50 (50 kg N ha–1 at preplant plus 50 kg N ha–1 at jointing stage) showed a promising lodging resistance with SFs, SFr and visual lodging scores similar to the zero N treatment. Taken together, the moderate split–N application (N50 + 50) is recommended due to the relative high grain protein (%) and strong lodging resistance while sustaining a promising yield. Spring wheat was more susceptible to root lodging than to stem lodging in the specific conditions of these experiments. Additionally, breeding for and cultivation with cultivars with improved stem strength is likely to be required to counter the escalating lodging risk arising from continued yield increases.

Generation of mutant lines of Nigella sativa L. by induced mutagenesis for improved seed yield

Nigella sativa L., an elegant herbaceous plant, envisaged immense medicinal potentials. It is widely used in pharmaceutical, food, and cosmetic industries. Economic market share of this plant and its products are not so significant because the seed yield and content of its bioactive compounds (especially thymoquinone) are low. To enhance the productivity and income of farmers, there is a need to develop high seed yielding germplasms of this plant. Given this, an attempt has been made in the present study to develop various mutant lines of N. sativa by inducing viable macro mutations through physical (gamma rays) and chemical (EMS) mutagens. These mutant lines differ in various phenotypical features, seed yield and thymoquinone content (TQ). Nine mutant lines were selected in M3 generation. These lines were high yielding tall (HY1) and semi dwarf (HY3); moderately high yielding tall (MHY2) and semi dwarf (MHY4); normal yielding dwarf (NY3); low yielding semi dwarf (LY1) and dwarf (LY3) and very low yielding dwarf (VLY2 and VLY3). The mutant lines also exhibited various other inherited peculiar characters including profused branches, feathery leaves, multicolored anthers, bilocular capsules, white seeds, etc. The HPLC analysis showed significant variations in the TQ content in all the mutant lines. The maximum content was reported in the seeds of dwarf mutants. Variations in the seed yield and content of thymoquinone among the mutant lines of Nigella sativa were due to mutagens-induced mutations. It may be concluded that ethyl methane sulphonate, gamma rays and their different combinations can be used efficiently to improve N. sativa and to induce genetic variability in this medicinal plant. The identified mutant lines that have high seed yield and high thymoquinone content may be explored for large-scale cultivation.

Marker-assisted foreground selection for identification of aromatic rice genotype to develop a modern aromatic line

Marker-assisted backcrossing is one of the feasible methods to develop a new kataribhog type rice cultivar with semi dwarf and modern type plant character to cope with the challenge. The study was focused on the introgression of Badh2 QTL from kataribhog into some elite promising line-an early, agronomically suitable and susceptible variety. Backcrossing was done during T.Aman season; where G52, GOR509, G27, G49 and IR 93358:4-B-21-4-3-1RGA-2RGA-1-B were the recurrent parent and kataribhog was the donor parent. At 1st season 160 true F1 and then in the next season 134 BC1F1 Plant were developed, which were subjected to foreground selection; the first level of selection of marker assisted backcrossing program. The aim of foreground selection was to identify the introgressed lines. 141 BC1F1 populations were evaluated with tightly linked BADEX7-5 marker. A total of 134 heterozygous BC1F1 Plant were selected finally, which have alleles of both of the parents. Those introgressed lines could be efficiently used in further development of a stable modern type aromatic rice variety

TNAU Rice CO 51 (IET 21605)-A high yielding short duration fine grain rice variety for Tamil Nadu

Early duration rice culture CB 06535,aderivative of the cross ADT 43 / RR 272 -1745wasreleased as TNAU Rice CO 51 during the year 2013 as an alternate variety to ADT 43 with 105 -110 days duration with additional desirable features like high yield, physiological efficiency and better adaptability. This culture with semi dwarf stature has efficient tillering capacity, long droopy panicles with highly acceptable plant characters and is a good replacement for the rice variety ADT 43 due to its high grain yield and pest and disease resistance. In the overall performance, the culture, CB 06 535 recorded a mean productivity of 6623 kg/ha in seven years of trials with 10.72 per cent increase over ADT 43. At Nallampalli, Dharmapuri district, the culture has recorded the highest yield of 11,377 kg/ha among the trials conducted, demonstrating the highest yield potential of this variety. The culture CB 06 535 is moderately resistant to blast, BPH and GLH under artificial condition. It produces medium slender white rice with intermediate amylose, soft gel consistency and moderate gelatinization temperature. It produces good quality cooked rice besides high milling and head rice recovery. CB 06 535 with higher yield, better pest and disease resistance and good cooking quality in comparison to the check ADT 43 is suitable for cultivation during Kar/ Kuruvai/Sornavari/Navaraiand the seasons / tracts wherever early maturing rice varieties are cultivated throughout Tamil Nadu.

Yield and Economic Potential of Spring‐Planted, Pea–Barley Forage in Short‐Season Corn Double‐Crop Systems

Core Ideas Biomass yield is similar between sole‐crop grain corn forage–silage corn double‐crop systems. Nitrogen fertilizer does not increase net economic return from forage–silage corn double‐crop systems. Double‐cro pea–barley forage–silage corn is not a profitable alternative to sole‐crop corn in the upper Midwest. Double cropping with forages can increase dry matter (DM) yield and N‐use efficiency over sole‐crop (SC) systems, but reductions in primary crop yield can limit economic return. This study assessed whether a double‐crop (DC) system coupling a legume–cereal biculture forage with early maturing corn can reduce fertilizer N input and compete economically with SC corn. Biomass yield, N uptake, residual soil NO3–N, and economic net return were measured in two DC and one SC systems in four experiments conducted in Minnesota between 2014 and 2016. In DC systems, a field pea (Pisum sativum L.)–barley (Hordeum vulgare L.) forage biculture was double cropped with a dual‐purpose hybrid (DP) or semidwarf (SD) corn (Zea mays L.) variety. In SC systems, full‐season hybrid corn (HC) was planted without preceding forage. Six fertilizer N rates (0–224 kg N ha−1) were applied to corn. Averaged across N rates, DP and SD corn yielded less (8.2 and 1.8 Mg DM ha−1, respectively) compared to SC (16.4 Mg DM ha−1). Total system DM yield was similar for the DC–DP and SC–HC systems, averaging 16.6 Mg ha−1. Economic return for the SC system was greater than that for the DC–DP system, and was maximized with 134 to 224 kg N ha−1, while return for the DC–DP system was unaffected by N rate. Due to low corn yield and greater production cost, double cropping spring forage with short‐season corn is not a profitable alternative to SC corn.