Heliotropium indicum L. has been shown to be very important in traditional healing medicine. However, many reports have indicated that the toxicity is not unconnected with pharmaceutical properties. This study therefore investigated the cytotoxic, genotoxic and biotoxic activities of methanolic leaf extract of H. indicum using Brine Shrimp lethality assay. The results revealed that the leaf extract of H. indicum showed lethality against the Brine Shrimps nauplii. The highest mortality was recorded at a concentration of 1000 μg/ml. The LC50 value of the Brine Shrimps mortality of the extract was recorded to be 461.04±10.02 μg/ml. In addition, the extract inhibited mitotic division in A. cepa root meristematic cells. The mitotic index was reduced from 59.99% in the control to 2.2% at 1000 μg/ml of the leaf extract. Chromosomal aberrations were observed at different concentrations. These include sticky chromosomes at metaphase and anaphase, chromosome breakage, degenerated and disoriented chromosomes at metaphase plate. It can be concluded from this present study that methanolic leaf extract of H. indicum was cytotoxic and genotoxic to Brine Shrimps and A. cepa cells respectively. Hence, caution should be exercised with respect to the consumption of H. indicum leaf in any form. © 2020 International Formulae Group. All rights reserved. Keywords: Mitotic index, chromosome aberrations, Brine Shrimps Lethality assay, Allium cepa assay, leaf extract

A plant that showed morphological closeness to Aspilia africana (Pers) C. D. Adams (Asteraceae) was spotted and collected in 2015 along Afe Babalola University road, Ado‐Ekiti, Ekiti State, Nigeria with coordinates 7°36′59.99″N, 5°12′60.00″E. However, upon closer observation some distinct and peculiar characteristics that clearly distinguished it from Aspilia africana were revealed, e.g. sterility of the disc florets and production of achenes by ray florets only. Another striking character of the plant was total emptying of the capitulum after achene maturation, leaving an empty capitulum cup on the plant. Literature and herbarium searches revealed that the plant had neither been reported from West Tropical Africa nor collected in any herbarium in Nigeria before. The plant was eventually identified as Melampodium divaricatum (L.) which is an annual erect herb, distributed in tropical and subtropical regions but mostly restricted to Mexico, North America and Central America. Morphological, reproductive and cytological studies carried out on the plant revealed it to possess a highly branched erect pigmented stem, simple opposite sub sessile leaves with acute apex and distantly serrated margins, capitula with yellow unisexual disc and ray florets, sterile disc florets, fertile ray florets, relatively high pollen fertility (92.85%), a somatic chromosome number of 2n = 24 and regular formation of 12 bivalents, indicating the plant to be a diploid species. Further studies on Melampodium in Nigeria and a general revision of the flora of West Tropical Africa is suggested as well as the need to monitor M. divaricatum in the region since it appears to have the capacity to become invasive.

This study explored the underlining reproductive factors that cause sterility in rice, using hybrids obtained from crosses among landrace selections and improved varieties. The study was carried out between 2016 and 2018. Nine landrace cultivars and two improved varieties were involved in the hybridization experiment. Among the 17 putative hybrids that were obtained, only 5 were confirmed as true hybrids. Meiotic chromosome studies and pollen studies in the F1, and Mendelian segregation studies for fertility in the F2 were carried out. Some F2 lines were monitored to F3 to ascertain the level of fixation of gene combinations for fertility. The results obtained from the chromosomal studies showed that phenomena such as laggards, precocious movements, formation of multivalents, and unequal segregation to the poles are associated with pollen sterility in all - 5 hybrids, at the F1 and F2 generations. The indehiscence of anthers contributed to infertility due to pollen shortage than the fertility of the pollens themselves. Even though in males, there is a preponderance of male sterility, female sterility is also a phenomenon that is possibly contributing to inter-varietal sterility. The segregational pattern of 13:3 was observed for fertility in the F2 which suggests the inhibition of fertility by a gene in the dominant state. There was the restoration of fertility in many of the lines advanced to the F3 to up to 93 % fertility. It was, therefore, concluded from the study that landraces of rice still hold the key for the rice crop improvement and should therefore be conserved.

Two landraces of rice, AWGUII-04 and IJ-124, were characterised and assessed for phenotypic variability, heritability, genetic advance and modes of inheritance of some primary yield and drought-tolerance traits. The target traits for yield were a percentage of filled spikelets, plant form, tillering, and for drought tolerance, leaf rolling, ratooning and maturity. This study was carried out to help both breeders and farmers make a wise choice when carrying out hybridisation and on the field. Hybridisation produced three F1 hybrids that were advanced to F2 generation. Quantitative and qualitative vegetative and reproductive data were taken from each F2 population. The results obtained showed high heritability (62–100%) in all the thirty-eight vegetative and reproductive traits. The genetic advance was high (> 20%) in all the target traits except for leaf rolling. The traits segregated in the following ratio: plant growth form – 9:6:1; the percentage of filled spikelets – 13:3; ratooning – 3:1; maturity – 15:1; the number of tillers – 15:1 and leaf rolling – 15:1. The high heritability of the above traits makes them highly dependable for rice crop improvement.