Iron (Fe) is an essential micronutrient for plants. Utilization of Fe deficiency-tolerant rootstock is an effective strategy to prevent Fe deficiency problems in fruit trees production. Malus halliana is an apple rootstock that is resistant to Fe deficiency; however, few molecular studies have been conducted on M. halliana. To evaluate short-term molecular response of M. halliana leaves under Fe deficiency condition, RNA sequencing (RNA-Seq) analyses were conducted at 0 (T1), 0.5 (T2) and 3 d (T3) after Fe-deficiency stress, and the timepoints were determined with a preliminary physiological experiment. In all, 6907, 5328, and 3593 differentially expressed genes (DEGs) were identified in pairs of T2 vs. T1, T3 vs. T1, and T3 vs. T2. Several of the enriched DEGs were related to heme binding, Fe ion binding, thylakoid membranes, photosystem II, photosynthesis-antenna protein, porphyrin and chlorophyll metabolism and carotenoid biosynthesis under Fe deficiency, which suggests that Fe deficiency mainly affects the photosynthesis of M. halliana. Additionally, we found that Fe deficiency induced significant down-regulation in genes involved in photosynthesis at T2 when seedlings were treated with Fe-deficient solution for 0.5 d, indicating that there was a rapid response of M. halliana to Fe deficiency. A strong up-regulation of photosynthesis genes was detected at T3, which suggested that M. halliana was able to recover photosynthesis after prolonged Fe starvation. A similar expression pattern was found in pigment regulation, including genes for coding chlorophyllide a oxygenase (CAO), β-carotene hydroxylase (β-OHase), zeaxanthin epoxidase (ZEP) and 9-cis-epoxycarotenoid dioxygenase (NCED). Our results suggest that pigment regulation plays an important role in the Fe deficiency response. In addition, we verified sixteen genes related to photosynthesis-antenna protein, porphyrin and chlorophyll metabolism and carotenoid biosynthesis pathways using quantitative real-time PCR (qRT-PCR) to ensure the accuracy of transcriptome data. Photosynthetic parameters, Chl fluorescence parameters and the activity of Chlase were also determined. This study broadly characterizes a molecular mechanism in which pigment and photosynthesis-related regulations play indispensable roles in the response of M. halliana to short-term Fe deficiency and provides a basis for future analyses of the key genes involved in the tolerance of Fe deficiency.

The present study was designed to assess genetic divergence between commercial bread wheat genotypes based on yield and its related traits and to carry out phenotypic correlation. Twenty bread hexaploid wheat varieties were assessed for mean performance, correlation analysis and genetic distance. Randomized complete block design was used with three replications during growing season, 2018-2019 at Wheat and Barley Research Institute, Tandojam. The mean squares depicted significant differences (P<0.01) for all the investigated traits among the tested genotypes, proving that used genetic resources possess a great potential for further breeding experiments. Regarding mean performance, the genotypes Sassui and TD-1 displayed desirable performance for a variety of traits, unveiling their importance in wheat breeding programs. The results also showed that tillers plant-1, grains spike-1 and seed index developed significantly positive (P<0.05) interrelationship with grain yield plant-1. This demonstrates that genotypes possessing higher extent of these traits may be chosen in selection for developing high yielding bread wheat genotypes. The larger genetic distance was witnessed between Johar-78 and TD-1, followed by SKD-1 and TJ-83, SKD-1 and Mehran-89, SKD-1 and Johar-78, TD-1 and Khirman, TJ-83 and Imdad-05, Mehran-89 and TD-1 and Johar-78 and TJ-83. These paired showed wide genetic distances, which may also be preferred in wheat hybridization program. Keywords: Genetic distance, hexaploid wheat, morphological traits, trait

Water stress is a primary constraint to achieve the goal of sustainable crop production. Water stress severely affects the seed production and oil yield of mustard genotypes. To overcome this problem, the development of water stress resilient mustard cultivars with potential seed and oil yield is a sustainable solution. Therefore, in vitro screening of mustard genotypes through PEG-6000 treatments were carried out on ten mustard genotypes. Along with control, two PEG-6000 levels were set to impose osmotic stress, such as, 6% and 10% PEG-6000. Data analyses depicted significant differences among all genotypes and between PEG-6000 treatments for all the studied traits, such as, shoot and root length, shoot and root fresh weight, shoot and root dry weight, K+ content, Ca++ content and K+/Ca++ ratio, demonstrating the availability of genetic differences in mustard genotypes for future stress breeding. Under PEG-6000 (6% and 10%) treatments, the genotypes like AARI-Canola, Khanpur Raya, Dhoom-1, Super Raya, Galaxy and Coral-432 exhibited high performance for seedling traits and less reduction due to PEG-6000 treatments. Hence, these mustard genotypes tend to provide useful genetic potential for water stress breeding. Keywords: Oilseed crops, genetic variations, drought stress, seed yield.

The wheat breeders are being focused to improve the yield potential of bread wheat by evolving new varieties with desirable genetic makeup in order to overcome the consumption pressure of ever increasing human population. For resolving this situation, a research was carried out on ten F2 populations along with their five parents grown in the Experimental Field, Botanical Garden, Department of Plant Breeding and Genetics, Sindh Agriculture University, Tandojam during the growing season of 2017-18. The experiment was carried-out in a randomized complete block design with four replications. The analysis of variance revealed significant differences among genotypes, parents and F2 crosses for all the traits studied. Such results signify the worth of breeding materials for further exploitation. Based on average performance, the parent AS-2002 and F2 cross Sehar-2006 × Kiran-95 showed promising performance for majority of studied traits including grain yield plant-1, showing their importance for future breeding programs. The genetic parameters indicated that from ten F2 progenies, Benazir × Sehar-2006displayed higher heritability estimates coupled with more genetic gain for maximum number of traits, showing a good parental combination for effective selection to improve wheat productivity in subsequent segregating generations.