Cultivation of okra in Ghana is challenged by low yield due to lack of improved varieties. Gamma irradiated okra seeds can generate genetic variability to improve the crop. Samples of 150 seeds, each of okra genotype, UCCC6, were irradiated with 400 Gy to 1000 Gy using cobalt 60 source at a dose rate exposure of 121.58 Gy/hr. There were 40 stands comprising single plant per stand in three replications per treatment in a randomized complete block design outlay. Seedling survival, plant height, number of leaves, stem diameter, number of branches, leaf length and width, days to 50% flowering, number of fruits, length and weight of fruit, number of seeds, and 100-seed weight decreased significantly ( ≤ 0.05) with increasing doses of gamma rays. Seedling survival was highest (88%) at 400 Gy, followed by control (81%). However, 600 Gy, 800 Gy, and 1000 Gy had 61%, 41%, and 17% seedling survival, respectively, with LD 50 at 720 Gy. Significant ( ≤ 0.05) correlations existed between growth and yield components. Optimum growth and yield in okra were induced by 400 Gy but the higher doses had growth retardation effects and the induced variability can be assessed at M 2 generation.

Background Invertases and their inhibitor proteins are key regulators of carbon allocation in plants. Manipulation of invertase inhibitor (ITI) activity can potentially increase crop yield. The aim of this study was to determine the sequence diversity, phylogenetic relationships, and expression profiles of ITI genes in sweetpotato (Ipomoea batatas). Results The results from DNA sequences from two sweetpotato varieties show that introns are absent in ITI homologs in the species. Two ITI paralogs were identified in sweetpotato (SPITI1 and SPITI2). Single nucleotide polymorphism (SNPs), insertions and deletions (Indels), and variable number of simple sequence repeats (SSR) were present in SPITI1, however, only SNPs were identified in SPITI2. The predicted SPITI1 proteins had 168, 172, or 174 amino acid residues, and molecular weights ranging from 17.88 to 18.38 kDa. In contrast, all SPITI2 sequences coded for predicted proteins with 192 amino acid residues, with molecular weight ranging from 20.59 to 20.65 kDa. All conserved domains of ITI proteins were present in both protein isoforms. Phylogenetic analysis indicated that both SPITI genes were more closely related to I.trifida and I.triloba than I.nil, thus, suggesting their evolutionary relationship and conservation. A qPCR study indicated that both SPITI genes were expressed in all the sample tissues, though relative expression values differed across different tissues at different developmental stages. Conclusions This is the first study reporting diversity of SPITI genes and of an ~ 18 kDA isoform in sweetpotato. The findings may enable design of genetic engineering strategies for SPITI genes, including CRISPR/Cas gene editing in sweetpotato.

Invertases and their inhibitor proteins are key regulators of carbon allocation in plants. Manipulation of invertase inhibitor (ITI) activity can potentially increase crop yield. The aim of this study was to determine the sequence diversity, phylogenetic relationships, and expression profiles of ITI genes in sweetpotato (Ipomoea batatas). The coding sequences of two ITI paralogs (SPITI1 and SPITI2) were cloned from two sweetpotato varieties (Beauregard and Jewel) and sequenced. The DNA sequences were used to deduce amino acids sequences and predicted protein properties. Quantitative PCR (qPCR) was carried out to study the expression profiles of the genes at different developmental stages. The results show that introns are absent in both SPITI paralogs. SNPs, Indels, and variable simple sequence repeats (SSR) were present in the SPITI1 paralog, however, only SNPs were identified in the SPITI2 paralog. The predicted SPITI1 protein had 168, 172, or 174 amino acid residues, and molecular weights ranging from 17.88 to 18.38 kDa. In contrast, SPITI2 coded for a protein with 192 amino acid residues, with molecular weight ranging from 20.59 to 20.65 kDa. All conserved domains of ITI proteins were present in both protein isoforms. Phylogenetic analysis indicated that SPITI genes were more closely related to I.trifida and I.triloba than I.nil, thus, suggesting their evolutionary relationship and conservation. A qPCR study indicated that both SPITI genes were expressed in all the sample tissues, though relative expression values differed across tissues at different developmental stages. This is the first study reporting diversity of SPITI genes and of an ~18 kDA isoform in sweetpotato. The findings may enable design of genetic engineering strategies for SPITI genes, including CRISPR/Cas gene editing in sweetpotato.