Exploitation of morphological features of bud and anther development for prediction of stages of microsporogenesis and microgametogenesis in pepper

Doubled haploid (DH) plant production assumes significant importance for breeders not only for mapping of genes of agronomic importance but also to shorten the breeding cycle for production of new hybrids and homogenous varieties. Microspore culture is the fastest method for production of doubled haploid plants. The success of haploid production in any species is dependent on the stage at which microspores or pollens are cultured, as this stage is crucial for switch from gametophytic to embryogenic mode of development of pollen in vitro. In the present investigation, we attempted to identify visible morphological markers in the flower bud and anthers in pepper (Capsicum annuum L.) for predicting the stages of growth of the microspores contained within them. Uninucleate microspore stage has been found to be most conducive stage for induction of androgenesis in pepper. In our study, the morphological markers for this stage were found to be: (i) size of flower bud in the range of 6-7 mm; (ii) length of anther approximately 450 µm; (iii) corolla slightly longer than that of the calyx; and (iv) green anthers with purple pigmentation at the apical end

Validation of PCR based detection system for aflatoxin producing molds.

Aflatoxins are polyketide secondary metabolites that are produced by certain fungal species in the Aspergillus section Flavi, particularly Aspergillus flavus and Aspergillus parasiticus which contaminate human food as well as animal feed. These are among the most carcinogenic substances known. Due to the toxic and carcinogenic properties of aflatoxins, there is a need to develop reliable methods to detect the presence of aflatoxigenic Aspergilli in contaminated food and feed. Not all Aspergillus strains are able to produce aflatoxins. It requires a detection methodology which can specifically distinguish between the aflatoxin producing and non-producing strains of Aspergillus. Present communication reports validation of a PCR based detection system based on three genes viz., nor-1, apa-2 and omt-1 involved in aflatoxin biosynthesis, that can specifically distinguish the two aflatoxin producing species viz. Aspergillus flavus and Aspergillus parasiticus from non-producers i.e., A. niger, A. fumigates and A. oryzae.

In vitro regeneration in olive (Olea europaea L.) cv, ‘Frontio’ from nodal segments.

An efficient and reproducible protocol for plantlet regeneration from nodal segments of Olive cv ‘Frontio’ has been developed. Media and explants browning due to exudation of phenolics from the explants were controlled by fortification of the medium with 100 mg/L ascorbic acid. Best establishment of olive explants was observed on half-strength MS salts fortified with 2.0 mg/L 6-benzylaminopurine (BAP), which resulted in 56.2% of bud break and 93.7% survival whereas, a combination of full strength MS medium with 1.0 mg/L each of 3-indole-butyric-acid (IBA) and kinetin was found to be the best for shoot multiplication, in terms of number of shoots (3.6 shoots/explant) and shoot length (2.2 cm). The in vitro shoots were rooted on half-strength MS medium fortified with 0.2 mg/L IBA and 0.2 mg/L α-naphthalene acetic acid (NAA) with 1.5 g/L activated charcoal, which supported optimum rooting (60 %), with an average of 2-3 roots/shoot, about 2.4 cm length were produced on four weeks of culture.

Use of meristem tip culture to eliminate carnation latent virus from carnation plants.

A successful protocol for meristem tip culture to eliminate carnation latent virus from carnation cv. scania has been described . The virus was found to be mechanically transmissible to Chenopodium quinoa, C. amaranticolor, Dianthus barbatus and Saponaria vaccaria. Murashige and Skoog'smedium (MS) supplemented with NAA (1.0 microM) and Kn (20.0 microM) proved best for meristem establishment and microshoots were rooted in MS medium supplemented with IBA (5.0 microM). Meristems measuring 0.1 and-0.2 mm yielded virus free plants and larger meristems were not effective.