Brassica rapa displays enormous morphological diversity, with leafy vegetables, turnips and oil crops. Turnips (Brassica rapa subsp. rapa) represent one of the morphotypes, which form tubers and can be used to study the genetics underlying storage organ formation. In the present study we investigated several characteristics of an extensive turnip collection comprising 56 accessions from both Asia (mainly Japanese origin) and Europe. Population structure was calculated using data from 280 evenly distributed SNP markers over 56 turnip accessions. We studied the anatomy of turnip tubers and measured carbohydrate composition of the mature turnip tubers of a subset of the collection. The variation in 16 leaf traits, 12 tuber traits and flowering time was evaluated in five independent experiments for the entire collection. The effect of vernalization on flowering and tuber formation was also investigated. SNP marker profiling basically divided the turnip accessions into two subpopulations, with admixture, generally corresponding with geographical origin (Europe or Asia). The enlarged turnip tuber consists of both hypocotyl and root tissue, but the proportion of the two tissues differs between accessions. The ratio of sucrose to fructose and glucose differed among accessions, while generally starch content was low. The evaluated traits segregated in both subpopulations, with leaf shape, tuber colour and number of shoots per tuber explaining most variation between the two subpopulations. Vernalization resulted in reduced flowering time and smaller tubers for the Asian turnips whereas the European turnips were less affected by vernalization.

Drought is a significant factor that causes yield loss in essential cereal crops such as sorghum [ Sorghum bicolor (L.) Moench], necessitating the development of drought‐tolerant varieties adaptable to various water conditions. This study aimed to pinpoint drought‐tolerant sorghum lines and genomic regions for tolerance by utilizing 216 sorghum accessions in stressed and non‐stressed environments at two locations. Genetic diversity was evident among accessions in terms of grain yield under different watering regimes. Drought stress indices such as the stress tolerance index, mean productivity, geometric mean productivity, harmonic mean productivity, yield stability index, and yield index were identified as effective measures for selecting drought‐tolerant sorghum. Cluster analysis classified genotypes into four groups based on their association with grain yield, highlighting Acc. #28546 and Acc. #216739 as highly drought tolerant across environments. This study identified 32 and 22 quantitative trait nucleotides (QTNs) for drought indices and grain yield under stress and non‐stress conditions, respectively, at two locations, with five common QTNs linked to multiple drought indices. Colocation analysis revealed that these QTNs were associated with known stay‐green‐related quantitative trait loci (QTLs), and 47 putative genes near these QTNs potentially influenced drought tolerance traits. It is suggested that accession selection considers multiple indices for robust evaluation. Understanding the identified genes and their functions provides insights into the genetic mechanisms governing plant responses to drought stress, offering prospects for developing improved drought‐resistant sorghum varieties through further genetic research.

The identification of genomic regions underlying the root system architecture (RSA) is vital for improving crop abiotic stress tolerance. To improve sorghum ( Sorghum bicolor L. Moench) for environmental stress tolerance, information on genetic variability and genomic regions linked to RSA traits is paramount. The aim of this study was, therefore, to investigate common quantitative trait nucleotides (QTNs) via multiple methodologies and identify genomic regions linked to RSA traits in a panel of 274 Ethiopian sorghum accessions. Multi‐locus genome‐wide association study was conducted using 265,944 high‐quality single nucleotide polymorphism markers. Considering the QTN detected by at least three different methods, a total of 17 reliable QTNs were found to be significantly associated with root angle, number, length, and dry weight. Four QTNs were detected on chromosome SBI‐05, followed by SBI‐01 and SBI‐02 with three QTNs each. Among the 17 QTNs, 11 are colocated with previously identified root traits quantitative trait loci and the remaining six are genome regions with novel genes. A total of 118 genes are colocated with these up‐ and down‐streams of the QTNs. Moreover, five QTNs were found intragenic. These QTNs are S5_8994835 (number of nodal roots), S10_55702393 (number of nodal roots), S1_56872999 (nodal root angle), S9_1212069 (nodal root angle), and S5_5667192 (root dry weight) intragenic regions of Sobic.005G073101 , Sobic.010G198000 , Sobic.001G273000 , Sobic.009G013600 , and Sobic.005G054700 , respectively. Particularly, Sobic.005G073101 , Sobic.010G198000 , and Sobic.009G013600 were found responsible for the plant growth hormone‐induced RSA. These genes may regulate root development in the seedling stage. Further analysis on these genes might be important to explore the genetic structure of RSA of sorghum.

Conventional propagation methods of sweet potato (Ipomoea batatas L. var Kulfo) through stem cutting require large amount of propagules and large space for preparation. It has high risk of disease transmission to the next generation. In vitro propagation is the best alternative to overcome such limitations. This study was conducted to optimize protocol for in vitro propagation of Kulfo sweet potato variety using 6-benzylaminopurine (BAP) and indole-3-butyric acid (IBA) phytohormones for shoot multiplication and rooting, respectively. The result revealed that the highest shoot initiation (77.78%) and shoot length (4.40 cm) was observed in MS media supplemented with 0.5 mg/l BAP. Best shoot multiplication (5.33 shoots per explants) was obtained in MS medium supplemented with 1 mg/l BAP. MS medium supplemented with 0.5 mg/l IBA showed 100% rooting and average root length of 7.44 cm in vitro. In ex vitro conditions, 93.33% rooting was recorded. During acclimatization, 84 and 93% survival of in vitro and ex vitro rooted plantlets, respectively, were recorded. It could be concluded that MS media without BAP provides optimal condition for shoot initiation. MS supplemented with 1 mg/l BAP provides optimum condition for shoot multiplication. The ex vitro rooting could be better option to reduce in vitro rooting cost and for increased plantlet survival during acclimatization. Based on the result, 0.5 mg/l BAP for shoot initiation, 1 mg/l BAP of shoot multiplication and directly transferring to soil for rooting was recommended for micropropagation of Kulfo sweet potato variety. However, further studies will be needed in ex vitro root induction. Key words: Sweet potato, micropropagation, shoot tip culture. Conventional propagation methods of sweet potato (Ipomoea batatas L. var Kulfo) through stem cutting require large amount of propagules and large space for preparation. It has high risk of disease transmission to the next generation. In vitro propagation is the best alternative to overcome such limitations. This study was conducted to optimize protocol for in vitro propagation of Kulfo sweet potato variety using 6-benzylaminopurine (BAP) and indole-3-butyric acid (IBA) phytohormones for shoot multiplication and rooting, respectively. The result revealed that the highest shoot initiation (77.78%) and shoot length (4.40 cm) was observed in MS media supplemented with 0.5 mg/l BAP. Best shoot multiplication (5.33 shoots per explants) was obtained in MS medium supplemented with 1 mg/l BAP. MS medium supplemented with 0.5 mg/l IBA showed 100% rooting and average root length of 7.44 cm in vitro. In ex vitro conditions, 93.33% rooting was recorded. During acclimatization, 84 and 93% survival of in vitro and ex vitro rooted plantlets, respectively, were recorded. It could be concluded that MS media without BAP provides optimal condition for shoot initiation. MS supplemented with 1 mg/l BAP provides optimum condition for shoot multiplication. The ex vitro rooting could be better option to reduce in vitro rooting cost and for increased plantlet survival during acclimatization. Based on the result, 0.5 mg/l BAP for shoot initiation, 1 mg/l BAP of shoot multiplication and directly transferring to soil for rooting was recommended for micropropagation of Kulfo sweet potato variety. However, further studies will be needed in ex vitro root induction. Key words: Sweet potato, micropropagation, shoot tip culture.