Development of Submergence-Tolerant, Bacterial Blight-Resistant, and High-Yielding Near Isogenic Lines of Popular Variety, ‘Swarna’ Through Marker-Assisted Breeding Approach

The rice variety ‘Swarna’ is highly popular in the eastern region of India. The farmers of eastern India cultivate mainly rainfed rice and face the adverse effects of climate change very frequently. Rice production in this region is not stable. Swarna variety is highly susceptible to bacterial blight (BB) disease and flash floods, which cause a heavy reduction in the yield. Transfer of five target genes/QTLs was targeted into the variety, Swarna by adopting marker-assisted backcross breeding approach. Direct markers for Sub1A, OsSPL14, and SCM2 QTLs and closely linked markers for xa5 and Xa21 BB resistance genes were screened in the backcross progenies. Swarna-Sub1, CR Dhan 800, and Swarna–Habataki near-isogenic lines (NILs) were used as donor parents in the breeding program. True multiple F1 plants were identified for backcrossing, and 796 BC1F1 seeds were generated. Foreground selection detected all the five target genes in six progenies in BC1F1 generation. The progeny containing all the target genes and more similar with the recipient parent was backcrossed, and a total of 446 BC2F1 seeds were produced. Foreground screening detected four BC2F1 plants carrying the five target genes. A total of 2,145 BC2F2 seeds were obtained from the best BC2F1 progeny. Screening of the progenies resulted in one plant with all five desirable genes, three plants with four, and another three progenies carrying three genes in homozygous conditions. The pyramided lines showed higher BB resistance and submergence tolerance than the recipient parent, Swarna. Culm strength of the pyramided lines showed higher breaking force than the recipient parent, Swarna. The pyramided line, SSBY-16-68-69 yielded the highest grain yield of 7.52 t/ha followed by the lines SSBY-16-68-511 (7.34 t/ha) and SSBY-16-68-1633 (7.02 t/ha). The best-pyramided line showed a yield advantage of 18% over the recipient parent and 6.8% over the yield component donor parent. Seven pyramided lines showed higher yield than the recipient parent, while five lines were better yielders than the yield component donor parent. The pyramided line SSBY-16-68-69 produced 365 grains/panicle, while the recipient had 152. The main morphologic and grain quality features of the recipient parent were retained in the pyramided lines.

Marker-Assisted Backcross Breeding for Improvement of Submergence Tolerance and Grain Yield in the Popular Rice Variety ‘Maudamani’

Submergence stress due to flash floods reduces rice yield drastically in sensitive varieties. Maudamani is a high yielding popular rice variety but is highly susceptible to submergence stress. The selection of progenies carrying Sub1 and GW5 (wide-grain) enhanced the submergence stress tolerance and grain yield of theMaudamani variety by following the marker-assisted backcross breeding method. Foreground screening detected 14 BC1F1, 17 BC2F1, and 12 BC3F1 backcross progenies that carried the target QTLs for submergence tolerance and grain width. Background screening was performed in the progenies carrying the target QTL and enhanced the recovery of a recipient parent’s genome by upto 96.875% in the BC3 pyramided line. The BC3F1 plant containing the highest recipient parent genome content and the target QTLs was self-pollinated. In BC3F2 generation, the target QTLs the Sub1 and GW5 (wide-grain) alleles and recipient parent’s yield component QTL OsSPL14 were tracked for homozygous states in the progenies. Seven pyramided lines showed tolerance to submergence for 14 days and higher grain yield than both the parents. The pyramided lines were similar to the recipient parent for the majority of the studied morphological and quality traits. The pyramided lines are useful as cultivars and can serve as potential donors for transfer of Sub1, OsSPL14, Gn1a, GW5 (wide-grain), and SCM2 QTLs.

GW10, a Member of P450 Subfamily Regulates Grain Size and Grain Number in Rice

Grain size and grain number play extremely important roles in rice grain yield. Here, we identify GW10 , which encodes a P450 subfamily protein and controlls grain size and grain number by using Lemont ( tropical japonica ) as donor parent and HJX74 ( indica ) as recipient parent. The GW10 locus was mapped into a 20.1 kb region on the long arm of Chromosome 10. Lower expression of the gw10 in panicle is contributed to the shorter and narrower rice grain, and the increased number of grains per panicle. Furthermore, the higher expression levels of some of the brassinosteroid (BR) biosynthesis and response genes are associated with the NIL- GW10 , which strongly suggests that the GW10 is a key node in the brassinosteroid-mediated regulation of rice grain shape and grain number.

Marker-Assisted Backcross Breeding for Improvement of Submergence Tolerance and Grain Yield in the Popular Rice Variety, ‘Maudamani’

Background: Submergence stress due to flash flood reduces rice yield drastically in sensitive varieties. Maudamani is a high yielding popular rice variety but highly susceptible to submergence stress. The Sub1 and yield component QTL, GW5 were transferred into the popular high yielding variety for enhancing submergence tolerance and yield. Methods: Sub1 and GW5 QTLs were transferred into Maudamani variety by adopting marker-assisted backcross breeding method. The target QTLs were selected by foreground selection in each backcross generation progenies to track the target QTLs. Recipient parent’s genome recovery was accelerated by adopting background selection in each backcross generation progenies carrying the target QTLs. Results: The two target QTLs were tracked in each backcross generation progenies by employing the tightly linked and direct markers. Background screening was performed in each backcross generation progenies carrying the target QTLs by using 57 background markers for enhancing the recovery of recipient parent’s genome content. The selected progenies containing highest genome recovery of the parent was hybridized with recipient parent, Maudamani. Finally, the selected BC3F1 plant containing highest recipient parent genome content and the two target QTLs was self-pollinated. In BC3F2 generation, two QTLs, Sub1 and GW5 along with recipient parent’s yield component QTLs, OsSPL14, Gn1a and SCM2 were tracked for their homozygous state in the progenies. Amongst the developed pyramided lines, six lines showed tolerance to submergence for 14 days and also exhibited higher grain yield than both the parents. The pyramided lines, MSS 607-116-541-117 and MSS 607-116-541-436 produced >9 t/ha grain yield showing an advantage of >5% over the popular recipient variety. Few pyramided lines were similar in appearance and quality traits with the recipient parent. Conclusion: The pyramided lines will be useful as potential donors for the QTLs Sub1+ OsSPL14+ Gn1a + GW5 + SCM2 and also as cultivars.

Xenia studies in exotic and indigenous almond (Prunus amygdalus L.) varieties of Kashmir, India

Pollination is very important to obtain an economic yield, and the selection of pollinizer with suitable quality and quantity of pollen is an essential practice in different fruit plants. The effects of pollen parent on kernel and nut characters are known to occur in several nut crops and to determine the best pollinizer and effect of pollen source on the nut and kernel quality of almond (Prunus amygdalus L.). The present investigation was carried out at the experiment farm of Dryland Agriculture Research Station (DARS), SKUAST-Kashmir for two consecutive years, i.e. 2008 and 2009. Various cross combinations were made among nine almond (three exotic and six indigenous) varieties/selections which are compatible with each other. Their nut and kernel characteristics were determined and observed maximum nut weight (2.21 g), nut length (39.78 mm) and nut breadth (20.33 mm), kernel weight (1.28 g), kernel length (28.63 mm) and kernel breadth (12.61 mm) and shelling percentage (57.99 %). In the present study it has been observed that the parent with big nut and kernel size and weight influenced the nut and kernel size; nut and kernel weight of the recipient parent significantly (p?0.05).

Verifikasi Lokus Aluminum Tolerance (Alt) pada Tiga Populasi BC3F1 Padi

Most of marginal lands in Indonesia are in the form of acid dry land with low available P and high Al concentrations. Development of tolerant rice varieties to P deficiency and Al toxicity is one way to increase rice production. This study aimed to select BC3F1-Pup1+Alt genotypes from three crosses based on foreground and background markers. This research was conducted at the Indonesian Center for Agricultural Biotechnology and Genetic Resources Research and Development, Bogor, from August to December 2015. The materials used were 300 genotypes of BC3F1 Dodokan-Pup1+Alt, BC3F1 Situ Bagendit-Pup1+Alt, BC3F1 Batur-Pup1+Alt, and the parents. The research included selection in modified Yoshida’s nutrient solutions (0.5 ppm P dan 60 ppm Al) followed by foreground selection and background selection. Selection using Yoshida’s nutrient solution resulted in 150 genotypes with longer root than the recipient parent in each of the BC3F1 populations. Selection with foreground markers using markers RM1361 and RM12031 produced 85 genotypes of BC3F1 Dodokan-Pup1+Alt (56.6%), 105 genotypes of BC3F1 Situ Bagendit-Pup1+Alt (70%), and 77 genotypes of BC3F1 Batur-Pup1+Alt (51.33%). Selection using background markers revealed that genotype number 116 (BC3F1 Dodokan-Pup1+Alt), number 2 (BC3F1 Situ Bagendit-Pup1+Alt), and number 129 (BC3F1 Batur-Pup1+Alt) were the best genotypes with percentage of parent recovery of 95%, 90%, and 90.5%, respectively. These three genotypes were verified to have Alt loci and had the largest genetic proportion of restoring parents. Keywords: Alt, background markers, foreground markers, Pup1, upland rice

Development of New Drought Tolerant Breeding Lines for Vietnam Using Marker-Assisted Backcrossing

Development of drought tolerant high-yielding varieties is essential because increased areas are subject to drought in the Mekong delta, Vietnam. The purpose of this experiment was developed using IR75499-73-1-B as drought tolerant donor and OMCS2000 as a recipient parent basis of a phenotypic and molecular marker for BC2F2 generation. Seven markers (RM219, RM201 RM105, RM23602, RM23877, RM24103 and RM328) were used for a idifying to drought tolerant. Primer RM23877 detected the highest number of lines as homozygous donor alleles (11 lines), followed by RM105 and RM201 (9 lines). The drought gene was introgressed into the new breeding lines. The plant height, number of tillers, and filled grain had positive correlation with yield/hill under drought stress. The lines BC2F2-45 and BC2F2-54 developed as drought tolerant, and gave high yield. This is an opportunity to improve breeding for high yield and drought tolerant rice varieties in Vietnam.

Incorporation of Bacterial Blight Resistance Genes Into Lowland Rice Cultivar Through Marker-Assisted Backcross Breeding

Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae is a major disease of rice in many rice growing countries. Pyramided lines carrying two BB resistance gene combinations (Xa21+xa13 and Xa21+xa5) were developed in a lowland cultivar Jalmagna background through backcross breeding by integrating molecular markers. In each backcross generation, markers closely linked to the disease resistance genes were used to select plants possessing the target genes. Background selection was continued in those plants carrying resistant genes until BC3 generation. Plants having the maximum contribution from the recurrent parent genome were selected in each generation and hybridized with the recipient parent. The BB-pyramided line having the maximum recipient parent genome recovery of 95% was selected among BC3F1 plants and selfed to isolate homozygous BC3F2 plants with different combinations of BB resistance genes. Twenty pyramided lines with two resistance gene combinations exhibited high levels of tolerance against the BB pathogen. In order to confirm the resistance, the pyramided lines were inoculated with different X. oryzae pv. oryzae strains of Odisha for bioassay. The genotypes with combination of two BB resistance genes conferred high levels of resistance to the predominant X. oryzae pv. oryzae isolates prevalent in the region. The pyramided lines showed similarity with the recipient parent with respect to major agro-morphologic traits.

Marker-assisted Foreground Selection for Identification of Salt Tolerant Rice Genotypes

ErratumIn the paper entitled “Marker-assisted Foreground Selection for Identification of Salt Tolerant Rice Genotypes” published in The Agriculturists 10(2): 1-8 (December 2012), the authors should be read as M. S. Alam, S. N. Begum, M. M. Islam, M. Moniruzzaman and M. A. K. Patwary instead of M. S. Alam, M. Salim, M. Moniruzzaman, J. A. Rashid and M. M. Islam (Authors changed on the online version on 13th June 2013).Marker Assisted Selection (MAS) technique was used to develop salt tolerant rice genotypes using molecular markers during June 2009 to November 2010 in the experimental field and Biotechnology Laboratory of Plant Breeding Division, Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh. FL-378 was identified as donor or male parent for saltol QTL and Binadhan-7 as recurrent or recipient parent which had high yield with short life cycle. Crossing was done between them and 10 F1 seeds were produced. PCR bands from all the 10F1 plants were scored as “H” represented heterozygous alleles for donor and recipient parent. Backcrossing was done to produce 105 BC1F1 seedlings. Foreground selection was performed with 72 BC1F1plants with a tightly linked salt tolerance marker RM21. Out of 72 plants, 33 plants were selected for RM21 showing ‘H’ scores. The selected segregants were subjected to further recombinant and background selections at BC1F1 generation. These selected genotypess could be used for further foreground, recombinant and background selections with appropriate markers upto BC3 generation for the development of salt tolerant rice genotypes. DOI: http://dx.doi.org/10.3329/agric.v10i2.13128 The Agriculturists 2012; 10(2) 1-8

Undue Influence as a Family Affair

Siblings sharing responsibility for parent care, and entitlement to parent assets, are sometimes dissatisfied with how their parents’ estates are distributed following a period of care to the parent. Such dissatisfaction can be advanced through legal claims by some siblings that other siblings, during the course of giving care, exerted undue influence over the parent to obtain their assets. The Canadian legal doctrine of undue influence directs attention to what transpired between two parties in the interest of protecting vulnerable people from having to honor arrangements to which they did not truly consent. In these cases, the focus is on the relationship between a sibling as an adult child, and the now deceased care recipient parent. At the same time, these cases reflect expectations and dynamics among siblings relative to each other. In this paper, a family, rather than dyadic, perspective is employed to illuminate elements of undue influence claims that are relevant to the sibling experience of giving care and sharing assets. We thus expand on understandings of dyadic issues addressed by the courts.