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Pineapple (Ananas comosuss, var. Smooth cayenne), which is a popular tropical fruit, is propagated vegetatively. Conventional propagation alone does not provide clean and adequate planting material demanded in Ethiopia. Recently, in vitro multiplication has become a promising technique for large-scale production. However, the acclimatization to the external environment procedure impedes the efficiency, which needs carefully optimized acclimatization techniques. We report optimized acclimatization procedures following first- and second-stage hardening methods for in vitro pineapple plantlets. Primarily, Jiffy-7 peat pellet allowed growing plants vigorously and provided above 8% survival rate over soil mix. Nevertheless, in Ethiopia, soil mix is cheaper and locally accessible. The primarily acclimatized plantlets are needed to be hardened further for better establishment and survival in the field. Black polybag and polysleeve pots filled with soil mix were evaluated in the greenhouse. A significant difference was obtained between pots for number of roots and substrate weight. Polybags had higher root number than polysleeves and saved about 27% of substrates per plant, which is a reduction of 25% of total transportation cost. Hence, the soil mix and polybags were found to be preferable over substrates and pots, for subsequent in vitro pineapple acclimatization.

Grape-berries are exposed to a plethora of abiotic and biotic stimuli during their development. The developmental and temporal regulation of grape berry polyphenol metabolism in response to various cues was investigated using LC-QTOF-MS based metabolite profiling. High light (2500μmolm(-2)s(-1)), high temperature (40°C), jasmonic acid (200μM), menadione (120μM) and abscisic acid (3.026mM) treatments were applied to detached berries. Greater magnitudes of metabolite fluctuations characterize the pre-veraison berries than the veraison stage in response to the treatments. Furthermore, a tighter co-response of metabolic processes was shown at veraison, likely supporting the resilience to change in response to stress. High temperature and ABA treatments led to greater magnitudes of change during the course of the experiment. The present study demonstrates the occurrence of differential patterns of metabolic responses specific to individual cues and berry developmental stage, which in the field are commonly associated and thus hardly discernable.

Ginger ( Zingiber officinale Rosc.) is the second most widely cultivated spice in Ethiopia, next to chilies. Recently, there has been huge demand for clean planting material of improved ginger cultivars, though it is difficult to meet the demand of planting materials using the conventional propagation techniques due to production inefficiency and disease transmission. Therefore, the present study was carried out with the objective of assessing the potential of axillary buds and shoot tips as explant sources and determination of suitable growth regulators for in vitro propagation of two ginger cultivars. Murashige and Skoog (MS) medium with four levels of benzyl adenine (BA) and kinetin was used for shoot multiplication in combination with two explant sources. A highly significant difference (p