Breeding crops in a conventional way demands considerable time, space, inputs for selection, and the subsequent crossing of desirable plants. The duration of the seed-to-seed cycle is one of the crucial bottlenecks in the progress of plant research and breeding. In this context, speed breeding (SB), relying mainly on photoperiod extension, temperature control, and early seed harvest, has the potential to accelerate the rate of plant improvement. Well demonstrated in the case of long-day plants, the SB protocols are being extended to short-day plants to reduce the generation interval time. Flexibility in SB protocols allows them to align and integrate with diverse research purposes including population development, genomic selection, phenotyping, and genomic editing. In this review, we discuss the different SB methodologies and their application to hasten future plant improvement. Though SB has been extensively used in plant phenotyping and the pyramiding of multiple traits for the development of new crop varieties, certain challenges and limitations hamper its widespread application across diverse crops. However, the existing constraints can be resolved by further optimization of the SB protocols for critical food crops and their efficient integration in plant breeding pipelines.

Melia azedarach L. commonly called Maha Neem is an economically and industrially important tree species with global significance. Although species possess versatile importance worldwide, information on reproductive biology and breeding system is scarce and limited for eastern coastal plain of India. Therefore, current study provides a detailed report on reproductive biology of M. azedarach. Maha Neem was found to bear violet to whitish violet, slightly fragrant, 14.99 ± 0.05 mm. long and 17.01 ± 0.08 mm. wide flowers. This tree commenced opening of floral buds during March and continued until May with a peak during March-end. The anthesis of species peaked between 08:00 and 10:00 am, which coincides with insect activity. Anthers were observed to dehisce during or shortly before anthesis; however, stigma started receptivity before anthesis and continued invitation up to 12 h after anthesis. Pollen viability ranged from 96.67 ± 1.6% to 98.26 ± 1.2 at the time of anthesis; after that decreased rapidly. Pollen: ovule ratio of 1096.38 ± 108.70 indicated the possibility of autogamy. The breeding system of M. azedarach revealed that fruit sets under natural pollination (NP) were significantly higher than Xenogamy. However, substantial difference was not reported in fruit set percentage under natural pollination and Autogamy, which is strong evidence in favour of self-pollination. Moreover, Maha-Neem is entomophilous with frequent visits by Apis and Syrphid flies. Current findings will be helpful in designing potent conservation strategies and planning successful breeding programmes.

Casuarina equisetifolia L. commonly called whistling pine is an economically and industrially important tree species with global significance. Although species possess versatile importance worldwide, efforts imparted for selection and designing a robust model of selection index are inadequate. The selection process, based on quantitative and qualitative traits, identified 15 superior trees from the eastern coastal plain of Odisha. These superior trees showcased exceptional qualitative and quantitative attributes. Correlation analysis highlighted key similarities among various traits like volume and above ground biomass (AGB), volume and diameter at breast height (DBH), DBH and AGB, DBH and Tree Height (TH), crown length (CL), height, AGB and height. Principal component analysis emphasized substantial contributions of traits like DBH, height, CL, crown width, AGB and volume across different clusters. Furthermore, culmination resulted in a comprehensive selection index, integrating both qualitative and quantitative characters, reaching 52.04, signifying superior performance among specific accessions. The current study provides valuable insights into selection and designing optimal selection index of C. equisetifolia, guiding future decisions concerning optimal wood production and resource management.