Genome wide analysis of recurrent parent genome recovery in different backcross populations for blast resistance through SSR markers in rice

Marker-assisted backcross breeding technique has been widely applied for incorporation of blast resistance genes into rice varieties. The monitoring of resistance genes along with recovery of recurrent parent is an essential aspect for reducing the donor genome content in backcross population. Current research was conducted to determine the recovery of recurrent parent in each backcross population of rice. Malaysian high yielding but blast susceptible rice variety MR219 was taken as recurrent parent while PongsuSeribu 2 was donor parent. Microsatellite markers commonly called as Simple sequence repeat markers were used to estimate recovery of recurrent parent genome i.e. MR219 in early generation of backcross population. A total of 300 microsatellite markerswere randomly applied on 12 rice chromosomes. 72 SSR markers found distinct and clear polymorphic between the parent PongsuSeribu 2 and MR219. These 72 polymorphic markers were utilized to analyze the recovery of plants in further subsequent generations. The background recovery ranged from 73-93.9% and 79- 96.3% in BC1F1 and BC2F1 generation. The proportion of recurrent parent genome increased and donor genome content decreases after every backcross generation. The recovery of recurrent parent genome content ranged from 94-97.1% in the selected improved advance lines of BC2F2 generation. In the advance lines, the average percent for the proportion of recurrent parent genome was 96.16%. Marker-assisted backcrossing efficiently accelerated the recurrent parent genome recovery within few backcrosses, reduced the backcross generation and saved plenty of time to intogress the genes against blast disease. The present results will be helpful for rice breeders for selecting true blast resistant lines along with maximum resemblance with recurrent parent

Morpho-physiological responses in wheat (Triticum aestivum L) influenced by normal and water stress conditions

Drought is a disaster around the world accumulating salt and erosion in lands. Presently, a research was conducted to determine the mor-pho-physiological response in bread wheat under normal and stress irrigations. This experiment was conducted at the experimental field of Sindh Agriculture University, Tandojam, Hyderabad, Pakistan, for two consecutive years during the Rabi season of the year 2011-12 and 2012-13. Stress was imposed by withholding irrigations at three dif-ferent growth stages of the plant, i.e. T1: normal irrigations applied, T2: stress at tillering stage, and T3: stress at the booting stage. The progenies Sarsabz x Khirman and Sarsabz x TD-1 contributed the highest heritability% (81.0% and 85.5%) for osmotic potential (-MPa) at stress at booting stage. For grain yield spike-1(g), the progeny Kiran-95 x Khirman showed maximum heritability as 84.37 in T3. However, the progeny TD-1 x Imdad proved to be the best combiner progeny indicating highest heritability percentage (91.0%) among the progenies for grain yield at booting stress