Evaluation of advanced back cross lines for drought tolerance in rice (Oryza sativa L.)

Drought is the largest abiotic constraint to rice production which cause significant yield loss depending upon the severity. Development of rice varieties with tolerance to drought and high use water use efficiency is the need of the hour. Despite the importance of drought as major abiotic constraint, the efforts to develop drought tolerant rice varieties are very low. Breeding efforts until recent past were focused on understanding and improvement of secondary traits that are putatively associated with drought tolerance. However, the genetic gain in yield by improvement of secondary traits is very low. Hence, improvement of yield per se under drought conditions will be better solution. Introgression of yield QTLs under drought in the genetic background of high yielding varieties will be helpful to overcome the problem to a certain extent. In the present study, 31 advanced back cross lines (BILs) derived from drought susceptible mega variety Samba Mahsuri (BT 5204) and a drought tolerant tolerant land race Azucena were evaluated under drought. Thirty one advanced back cross inbred lines (BC2F4) lines having yield QTLs viz., qDTY3.1 on chromosome 3 and qDTY2.1 on chromosome 2 were phenotyped under drought conditions. The results suggested that wide range of variation was observed for yield and its component traits in the BILs generated in the background of BPT 5204 and direct selection for yield under water stress coupled with marker assisted screening would help in development of drought tolerant version of mega varieties with improved yield under stress. Thermo tolerance studies indicated that high variability was observed for the BILs in terms of % seedling survival, % reduction in root and shoot growth under stress.

Variability and inheritance of fiber length and wilt resistance in a complex 4-5 specific and backcross hybridization of cotton

In this paper presents data of researches about fiber length in the 4-5 species. The largest number of plants with the indicated analyzed trait in hybrid combinations, obtained with the participation of the variety Omad, appeared with a number of variations in fiber length at 35,0-36,0 mm and above. Investigation of 4-species hybrids of F2 and back cross hybridization allowed some improvement in the average value of trait when compared with F1. Despite the emergence of transgressive plants with fiber length 36,1-37,0 mm and above, the average trait of composite 5 species hybrids F2 remained almost at the level of F1, i.e. 35.5-36.0 mm. The greatest number of positive recombinants occurred in 5 species back crossing developed with the participation of Termez-31.

Variability and inheritance of fiber length and wilt resistance in a complex 4-5 specific and backcross hybridization of cotton

In this paper presents data of researches about fiber length in the 4-5 species. The largest number of plants with the indicated analyzed trait in hybrid combinations, obtained with the participation of the variety Omad, appeared with a number of variations in fiber length at 35,0-36,0 mm and above. Investigation of 4-species hybrids of F2 and back cross hybridization allowed some improvement in the average value of trait when compared with F1. Despite the emergence of transgressive plants with fiber length 36,1-37,0 mm and above, the average trait of composite 5 species hybrids F2 remained almost at the level of F1, i.e. 35.5-36.0 mm. The greatest number of positive recombinants occurred in 5 species back crossing developed with the participation of Termez-31.

The Blonde d’Aquitaine T3811>G3811 mutation in the myostatin gene: association with growth, carcass, and muscle phenotypes in veal calves

The mutation T3811 → G3811 (TG3811) discovered in the myostatin gene of the Blonde d’Aquitaine breed is suspected of contributing to the outstanding muscularity of this breed. An experiment was designed to estimate the effect of this mutation in an F2 and back-cross Blonde d’Aquitaine × Holstein population. By genotyping all known mutations in the myostatin gene, it was ensured that the TG3811 mutation was indeed the only known mutation segregating in this population. Fifty-six calves (43 F2, 13 back-cross) were intensively fattened and slaughtered at 24.0 ± 1.4 wk of age. The effects of the mutation were estimated by comparing the calves with the [T/T] (n = 18), [T/G] (n = 30), and [G/G] (n = 8) genotypes. Highly significant substitution effects (P < 0.001), above + 1.2 phenotypic SD, were shown on carcass yield and muscularity scores. Birth weight (P < 0.001) was positively affected by the mutation (+0.8 SD) but not growth rate (P = 0.97), while carcass length (P = 0.03), and fatness (P ≤ 0.03) were negatively affected (–0.5 to –0.7 SD). The characteristics of the Triceps brachii muscle were affected by the mutation (P < 0.001), with lower ICDH activity (oxidative) and a higher proportion of myosin type 2X muscle fibers (fast twitch). The effects of the TG3811 mutation were similar to those of other known myostatin mutations, although the Blonde d’Aquitaine animals, which are predominantly [G/G] homozygous, do not exhibit extreme double muscling.

Concentrated Noir: Reinforcing and transgressing genre boundaries in Echo

Nordic Noir has emerged as an increasingly codified set of aesthetic, political and philosophical televisual elements. Echo compresses these elements, subjecting them to the crucible of short film. This article investigates the dramatic potential of stripping back cross-genre tropes to reveal the defining characteristics of a newly emergent format.

Improvement of Stable Restorer Lines for Blast Resistance through Functional Marker in Rice (Oryza sativa L.)

Two popular stable restorer lines, CB 87 R and CB 174 R, were improved for blast resistance through marker-assisted back-cross breeding (MABB). The hybrid rice development program in South India extensively depends on these two restorer lines. However, these restorer lines are highly susceptible to blast disease. To improve the restorer lines for resistance against blasts, we introgressed the broad-spectrum dominant gene Pi54 into these elite restorer lines through two independent crosses. Foreground selection for Pi54 was done by using gene-specific functional marker, Pi54 MAS, at each back-cross generation. Back-crossing was continued until BC3 and background analysis with seventy polymorphic SSRs covering all the twelve chromosomes to recover the maximum recurrent parent genome was done. At BC3F2, closely linked gene-specific/SSR markers, DRRM-RF3-10, DRCG-RF4-8, and RM 6100, were used for the identification of fertility restoration genes, Rf3 and Rf4, along with target gene (Pi54), respectively, in the segregating population. Subsequently, at BC3F3, plants, homozygous for the Pi54 and fertility restorer genes (Rf3 and Rf4), were evaluated for blast disease resistance under uniform blast nursery (UBN) and pollen fertility status. Stringent phenotypic selection resulted in the identification of nine near-isogenic lines in CB 87 R × B 95 and thirteen in CB 174 R × B 95 as the promising restorer lines possessing blast disease resistance along with restoration ability. The improved lines also showed significant improvement in agronomic traits compared to the recurrent parents. The improved restorer lines developed through the present study are now being utilized in our hybrid development program.

Penampilan Fenotipik Populasi Dasar Jagung Pulut Lokal Sulawesi Selatan dengan Seleksi Back Cross

This research aims to see the phenotypic appearance of selected families from the basic population of local waxy corn of South Sulawesi which is back cross with the parents. The technique of crosses used is repeated selection that is to make a cross between selected families (recombination) by means of free crossing. The number of cross-test of 5 selected families and 5 varieties of comparison (parents) with 2 replications. Each replica was planted with 10 lines of 20 lines of with 20 cm x 50 cm spacing), the total number of plants in this research were 400 plants. Each line represented 5 sample plants, so the total sample of 200 plants. The results showed that from 5 selected families who crossed with their parents as a whole can improve the phenotype character. The selected local waxy corn has a superior appearance of the phenotype character. Of the 200 plant samples, there are 75 plants that have superior appearance (better phenotype appearance than their parents) on the character : plant height , the height of cob location, male flowering, female flowering, and husk cover.